diff --git a/changelog.d/1275-forecast-issue-fix.md b/changelog.d/1275-forecast-issue-fix.md
new file mode 100644
index 000000000..2013bc4f2
--- /dev/null
+++ b/changelog.d/1275-forecast-issue-fix.md
@@ -0,0 +1,3 @@
+- Preserve enable during first-load replacement (asturksever, #1275).
+- Release disabled weather camera listeners and make teardown resource leaks fail the browser probe (asturksever, #1275).
+- Keep visible-page weather teardown probes focused through the browser testing API (asturksever, #1275).
diff --git a/changelog.d/1276-terrain-issue-fix.md b/changelog.d/1276-terrain-issue-fix.md
new file mode 100644
index 000000000..17e8f4b50
--- /dev/null
+++ b/changelog.d/1276-terrain-issue-fix.md
@@ -0,0 +1 @@
+- Bound each height request to one upstream chunk (asturksever, #1276).
diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index 814c78e01..fafcb9a54 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -9,10 +9,10 @@ broader suffix variants. Follow-ups retain boundary provenance, and cancelled
 lookups preserve the previous analyst cohort and boundary source. Navigation
 search keeps a successful geocode, with no search or view-based region recovery.
 
-Share links and structured views accept only own keys in their style registries.
-Inherited names such as `constructor` and `__proto__` fall back to the existing
-normal/null defaults without interrupting other restored fields. Programmatic
-visual-style calls ignore unknown or non-string values before mutating state.
+Terrain height requests accept at most 64 points, matching the browser service's
+existing batch size and one bounded upstream chunk. Larger requests return HTTP
+413 before disk-cache loading or upstream work; malformed coordinates remain 400.
+The browser continues to split larger workloads into sequential 64-point requests.
 
 Shared distance checks use `src/geoDistance.js` with `{ lat, lon }` points and
 the IUGG mean spherical Earth radius, 6371.0088 km. `greatCircleKm` is
@@ -275,6 +275,7 @@ catalog construction owns each instance.
 
 Wind animates one forecast without advancing forecast time. Separate Weather
 observation layers provide radar and satellite history; none claims measured cloud volume.
+Weather imagery releases its camera move listener on disable and registers it once on re-enable. Disabling also clears active imagery work.
 Weather imagery drapes onto the globe basemap. On photorealistic 3D Tiles each
 observed product is instead a raised, translucent shell: one rectangle over the
 product bounds at a fixed height (global infrared 5.5 km, regional infrared
diff --git a/scripts/qa-weather-teardown.mjs b/scripts/qa-weather-teardown.mjs
index b64d1d59c..bf7b00269 100644
--- a/scripts/qa-weather-teardown.mjs
+++ b/scripts/qa-weather-teardown.mjs
@@ -61,6 +61,10 @@ const browser = await puppeteer.launch({
 
 const boot = async () => {
   const page = await browser.newPage();
+  // This probe measures active rendering; an OS-minimized window must not
+  // silently exercise the application's intentional hidden-page pause.
+  const focus = await page.createCDPSession();
+  await focus.send('Emulation.setFocusEmulationEnabled', { enabled: true });
   await page.setViewport({ width: 1400, height: 920, deviceScaleFactor: 1 });
   const errors = [];
   page.on('pageerror', (e) =>
@@ -141,7 +145,7 @@ const snapshot = (page) =>
         ),
       },
       weather,
-      windCells: wind.gpu?.pathCount ?? wind.paths ?? null,
+      windCells: wind.gpu?.pathCount ?? wind.paths ?? 0,
       enabled: [...dm.layers].filter(([, e]) => e.enabled).map(([id]) => id),
     };
   });
@@ -220,7 +224,7 @@ try {
   const baseline = await snapshot(a.page);
   console.log('baseline', JSON.stringify(baseline));
   for (const id of WEATHER) await setLayer(a.page, id, true);
-  await a.page
+  const weatherReady = await a.page
     .waitForFunction(
       () =>
         ['weather-radar', 'weather-satellite', 'weather-lightning'].every(
@@ -233,7 +237,13 @@ try {
         ),
       { timeout: 120_000 },
     )
-    .catch(() => console.log('  !! weather not ready'));
+    .then(
+      () => true,
+      () => false,
+    );
+  results.weatherReady = weatherReady;
+  if (!weatherReady)
+    console.log('  !! weather not ready — feature coverage incomplete');
   await sleep(2000);
   // exercise: history playback, wind reading, storm selection, product switch
   await a.page.evaluate(() => {
@@ -331,11 +341,25 @@ try {
     'errors (control run):',
     results.errorsB.length ? results.errorsB : 'none',
   );
+  // Resource ownership is an acceptance check; provider availability remains
+  // separately reported diagnostic evidence in both runs.
+  if (
+    !weatherReady ||
+    Object.keys(leak).length ||
+    [...a.errors, ...b.errors].some((e) => e.startsWith('pageerror:'))
+  ) {
+    process.exitCode = 1;
+  }
+} catch (error) {
+  results.failure = { name: error.name, message: error.message };
+  throw error;
+} finally {
+  // Preserve completed resource evidence even if a later provider or browser
+  // phase aborts. A partial run still exits nonzero.
   writeFileSync(
     path.join(outDir, 'results.json'),
     JSON.stringify(results, null, 2),
   );
   console.log(`wrote ${path.join(outDir, 'results.json')}`);
-} finally {
   await browser.close();
 }
diff --git a/server/providers/terrain.js b/server/providers/terrain.js
index 32083d23a..c678ab7c0 100644
--- a/server/providers/terrain.js
+++ b/server/providers/terrain.js
@@ -20,8 +20,8 @@ import { admitSameSiteKeyless } from './common/same-site.js';
  * cache and serve-stale shape. Cache entries and stale fallback are keyed per
  * 5dp point, so reordered and partially overlapping batches reuse prior work.
  * Only missing/stale points go upstream; the response is rebuilt in exact
- * request order. Larger requests are chunked sequentially, and one failing
- * chunk does not discard the chunks that resolved.
+ * request order. Each request is bounded to one 64-point upstream chunk;
+ * larger client workloads are split by the browser terrain service.
  *
  * Bounds, because every distinct 5dp point is its own key: coordinates must be
  * in WGS-84 range (rejected at parse), the point cache has an entry ceiling
@@ -55,7 +55,7 @@ export function terrainHeightsProxy(options = {}) {
   // 2026-08-21). 64 points costs 5.6-12 s, inside the timeout at both ends of
   // that range.
   const UPSTREAM_CHUNK = 64;
-  const MAX_POINTS = 2000;
+  const MAX_POINTS = UPSTREAM_CHUNK;
   /**
    * Entry ceiling for the point cache, and with it the file written from it.
    *
@@ -255,7 +255,6 @@ export function terrainHeightsProxy(options = {}) {
           res.end(JSON.stringify({ error: 'Rate limit exceeded' }));
           return;
         }
-        await loadDiskOnce();
         const parsedUrl = new URL(req.url || '', 'http://internal');
         const rawPoints = parsedUrl.searchParams.get('points');
         const points = parseTerrainPoints(rawPoints);
@@ -267,12 +266,13 @@ export function terrainHeightsProxy(options = {}) {
           return;
         }
         if (points.length > MAX_POINTS) {
-          send(500, {
+          send(413, {
             error: `too many points (${points.length}); max ${MAX_POINTS} per request`,
           });
           return;
         }
 
+        await loadDiskOnce();
         const outcome = await resolveTerrainHeightRequest({
           points,
           cache: mem,
diff --git a/src/layers/weather/index.js b/src/layers/weather/index.js
index db62ea98a..757764fe6 100644
--- a/src/layers/weather/index.js
+++ b/src/layers/weather/index.js
@@ -296,10 +296,6 @@ export function createWeatherLayer({
       motion?.addEventListener?.('change', onVisibility);
       documentRef?.addEventListener?.('visibilitychange', onVisibility);
       registerClock();
-      removeCamera = viewer.camera.moveEnd?.addEventListener(() => {
-        checkHost();
-        if (enabled) notify();
-      });
     },
     attachShellServices(services) {
       imageryHost =
@@ -315,10 +311,18 @@ export function createWeatherLayer({
     },
     enable() {
       enabled = true;
+      if (!removeCamera) {
+        removeCamera = viewer.camera.moveEnd?.addEventListener(() => {
+          checkHost();
+          notify();
+        });
+      }
       registerClock();
     },
     disable() {
       enabled = false;
+      removeCamera?.();
+      removeCamera = null;
       unregisterClock?.();
       unregisterClock = null;
       ++generation;
@@ -357,7 +361,7 @@ export function createWeatherLayer({
           signal: controller.signal,
         });
         if (!enabled || controller.signal.aborted || request !== controller)
-          return false;
+          return enabled && !signal?.aborted && request !== controller;
         if (snapshot.unavailable) {
           error = msg(
             'Weather source unavailable; previous observation retained',
@@ -376,7 +380,9 @@ export function createWeatherLayer({
           )
             await show(snapshot.latest, controller.signal);
           return (
-            !controller.signal.aborted && request === controller && enabled
+            enabled &&
+            !signal?.aborted &&
+            (!controller.signal.aborted || request !== controller)
           );
         }
         const time =
@@ -388,9 +394,14 @@ export function createWeatherLayer({
           (satellite && rendering.getDiagnostics().infrared !== infrared)
         )
           await show(time, controller.signal);
-        return !controller.signal.aborted && request === controller && enabled;
+        return (
+          enabled &&
+          !signal?.aborted &&
+          (!controller.signal.aborted || request !== controller)
+        );
       } catch (cause) {
-        if (controller.signal.aborted || request !== controller) return false;
+        if (controller.signal.aborted || request !== controller)
+          return enabled && !signal?.aborted && request !== controller;
         error = cause?.message || msg('Weather unavailable');
         stop();
         return true;
diff --git a/src/layers/weather/weather.test.mjs b/src/layers/weather/weather.test.mjs
index 1a4ba5177..486d42520 100644
--- a/src/layers/weather/weather.test.mjs
+++ b/src/layers/weather/weather.test.mjs
@@ -694,7 +694,11 @@ test('superseding a pending stage preserves the newer manifest loading state', a
   await flush();
   const newer = h.layer.update();
   await flush();
-  assert.equal(await old, false);
+  assert.equal(
+    await old,
+    true,
+    'replacement is accepted by the enable lifecycle',
+  );
   assert.equal(
     h.layer.getStats().loading,
     true,
@@ -2311,3 +2315,44 @@ for (const product of ['radar', 'clouds-regional', 'lightning']) {
     assert.equal(h.viewer.camera.moveEnd.size, 0);
   });
 }
+
+test('a product replacement accepts supersession but never paints the obsolete first response', async () => {
+  const pending = [];
+  const h = layerHarness({
+    id: 'weather-satellite',
+    feed: {
+      getSnapshot: (args) => {
+        const task = deferred();
+        pending.push({ ...args, ...task });
+        return task.promise;
+      },
+    },
+  });
+  const first = h.layer.update();
+  h.layer.setParams({ product: 'clouds' });
+  assert.equal(pending.length, 2);
+  pending[0].resolve({ ...snapshot, product: 'clouds-regional' });
+  assert.equal(await first, true);
+  assert.equal(h.stages.length, 0);
+  pending[1].resolve({ ...snapshot, product: 'clouds' });
+  await flush();
+  h.stages.at(-1).finish();
+  await flush();
+  assert.equal(h.layer.getParams().product, 'clouds');
+  h.layer.destroy();
+});
+
+test('disabled weather releases its camera listener and re-enabling binds only once', () => {
+  const h = layerHarness();
+  h.layer.disable();
+  assert.equal(h.moveEnd.size, 0, 'disabled layers own no active camera work');
+  h.layer.enable();
+  h.layer.enable();
+  assert.equal(h.moveEnd.size, 1);
+  h.layer.disable();
+  assert.equal(h.moveEnd.size, 0);
+  h.layer.enable();
+  assert.equal(h.moveEnd.size, 1);
+  h.layer.destroy();
+  assert.equal(h.moveEnd.size, 0);
+});
diff --git a/src/layers/wind/index.js b/src/layers/wind/index.js
index c76e2501c..aa6161f06 100644
--- a/src/layers/wind/index.js
+++ b/src/layers/wind/index.js
@@ -180,7 +180,7 @@ export function createWindLayer({
           overlay: requestedScalar(),
         });
         if (!enabled || controller.signal.aborted || request !== controller)
-          return false;
+          return enabled && !signal?.aborted && request !== controller;
         manifest = snapshot;
         error = null;
         if (sampledPosition) sample(sampledPosition);
@@ -194,7 +194,8 @@ export function createWindLayer({
         }
         return true;
       } catch (cause) {
-        if (controller.signal.aborted || request !== controller) return false;
+        if (controller.signal.aborted || request !== controller)
+          return enabled && !signal?.aborted && request !== controller;
         error = cause?.message || msg('Wind source unavailable');
         return true;
       } finally {
diff --git a/src/layers/wind/index.test.mjs b/src/layers/wind/index.test.mjs
index ac843f62a..3b5e09697 100644
--- a/src/layers/wind/index.test.mjs
+++ b/src/layers/wind/index.test.mjs
@@ -412,3 +412,36 @@ test('wind unit chips appear only alongside a speed legend, including canvas tra
   for (const overlay of ['pressure', 'temperature', 'none']) { layer.setParams({ overlay }); assert.deepEqual(unitChips(), []); }
   layer.destroy();
 });
+
+test('a parameter replacement during manager enable does not roll the layer back', async () => {
+  const { LayerLifecycle } = await import('../../data/lifecycle.js');
+  const pending = [];
+  const rendering = Object.fromEntries(
+    ['attach', 'start', 'stop', 'clear', 'destroy', 'setField'].map((name) => [
+      name,
+      () => {},
+    ]),
+  );
+  const layer = createWindLayer({
+    feed: {
+      getSnapshot: (args) =>
+        new Promise((resolve) => pending.push({ ...args, resolve })),
+    },
+    createRendering: () => rendering,
+  });
+  const manager = new LayerLifecycle({ container: {} });
+  manager.register(layer);
+  const enabled = manager.setEnabled('wind', true);
+  for (let i = 0; i < 20 && !pending.length; i++) await Promise.resolve();
+  layer.setParams({ model: 'ifs' });
+  await Promise.resolve();
+  pending[0].resolve(snapshot('gfs'));
+  assert.equal(await enabled, true);
+  assert.equal(manager.isEnabled('wind'), true);
+  assert.equal(layer.getStats().loading, true);
+  pending[1].resolve(snapshot('ifs'));
+  for (let i = 0; i < 10; i++) await Promise.resolve();
+  assert.equal(layer.getStats().model, 'IFS');
+  assert.equal(layer.getStats().count, 4);
+  await manager.destroyAll();
+});
diff --git a/src/terrainHeightsBounds.test.mjs b/src/terrainHeightsBounds.test.mjs
index cd1a9ad36..3746f4fe4 100644
--- a/src/terrainHeightsBounds.test.mjs
+++ b/src/terrainHeightsBounds.test.mjs
@@ -366,3 +366,24 @@ test('a second client keeps its own quota', async (t) => {
   });
   assert.notEqual(neighbour.statusCode, 429);
 });
+
+test('one 64-point chunk is accepted; larger batches fail before cache or upstream work', async (t) => {
+  const root = await mkdtemp(path.join(tmpdir(), 'terrain-batch-limit-'));
+  t.after(() => rm(root, { recursive: true, force: true }));
+  const asked = stubTerrainUpstream(t);
+  const route = install(
+    terrainHeightsProxy({ cachePath: path.join(root, 'cache.json') }),
+  ).get('/api/terrain/heights');
+  const points = (count) =>
+    Array.from({ length: count }, (_, i) => `${i / 1000},30`).join(';');
+  for (const count of [65, 2001]) {
+    const response = await request(route, { url: `/?points=${points(count)}` });
+    assert.equal(response.statusCode, 413);
+    assert.match(response.body.error, /max 64/);
+    assert.equal(asked.length, 0);
+  }
+  const response = await request(route, { url: `/?points=${points(64)}` });
+  assert.equal(response.statusCode, 200);
+  assert.equal(response.body.results.length, 64);
+  assert.equal(asked.length, 64);
+});
diff --git a/src/tooling/environmentProviders.test.mjs b/src/tooling/environmentProviders.test.mjs
index b6faeb34c..bbb0e9d6e 100644
--- a/src/tooling/environmentProviders.test.mjs
+++ b/src/tooling/environmentProviders.test.mjs
@@ -98,7 +98,7 @@ test('standalone composition mounts every extracted provider exactly once withou
     assert.equal(plugins.filter((p) => p.name === factory().name).length, 1);
 });
 
-test('terrain middleware chunks missing points and reconstructs repeated/reordered requests from cache', async (t) => {
+test('terrain middleware bounds missing points and reconstructs repeated/reordered requests from cache', async (t) => {
   isolate(t);
   let calls = 0;
   const sizes = [];
@@ -116,25 +116,23 @@ test('terrain middleware chunks missing points and reconstructs repeated/reorder
     });
   });
   const request = install(terrainHeightsProxy());
-  const points = Array.from({ length: 257 }, (_, i) => `${i / 100},1`);
+  const points = Array.from({ length: 64 }, (_, i) => `${i / 100},1`);
   const res = await request('/?points=' + points.join(';'));
   assert.equal(res.status, 200);
-  // Tracks UPSTREAM_CHUNK in server/providers/terrain.js (64): 257 points
-  // split into four full chunks and a remainder.
-  assert.deepEqual(sizes, [64, 64, 64, 64, 1]);
-  const reordered = await request('/?points=2.56,1;0,1;2.56,1');
+  assert.deepEqual(sizes, [64]);
+  const reordered = await request('/?points=0.63,1;0,1;0.63,1');
   assert.deepEqual(json(reordered), {
-    results: [{ ellipsoid: 102.56 }, { ellipsoid: 100 }, { ellipsoid: 102.56 }],
+    results: [{ ellipsoid: 100.63 }, { ellipsoid: 100 }, { ellipsoid: 100.63 }],
   });
-  // Five chunks for the first batch; the reordered request is fully cached.
-  assert.equal(calls, 5);
+  // One bounded batch; the reordered request is fully cached.
+  assert.equal(calls, 1);
   assert.equal((await request('/?points=invalid')).status, 400);
   assert.equal(
     (await request('/?points=' + Array(2001).fill('0,1').join(';'))).status,
-    500,
+    413,
   );
-  // Rejected requests add no upstream calls: still the five from the first batch.
-  assert.equal(calls, 5);
+  // Rejected requests add no upstream calls.
+  assert.equal(calls, 1);
 });
 
 test('terrain middleware migrates valid legacy disk points without fabricating omitted heights', async (t) => {
@@ -388,21 +386,26 @@ test('terrain middleware retains successful chunks around a failure and retries
   });
   const request = install(terrainHeightsProxy());
   const points = Array.from({ length: 130 }, (_, i) => `${i / 100},1`);
-  const url = '/?points=' + points.join(';');
-  assert.equal((await request(url)).status, 502);
+  const urls = [0, 64, 128].map(
+    (start) => '/?points=' + points.slice(start, start + 64).join(';'),
+  );
   assert.deepEqual(
-    requests.map((p) => p.length),
-    [64, 64, 2],
+    await Promise.all(urls.map(async (url) => (await request(url)).status)),
+    [200, 502, 200],
+  );
+  assert.deepEqual(
+    requests.map((p) => p.length).sort((a, b) => a - b),
+    [2, 64, 64],
   );
   fail = false;
-  const recovered = await request(url);
-  assert.equal(recovered.status, 200);
+  const recovered = await Promise.all(urls.map((url) => request(url)));
+  assert.ok(recovered.every((response) => response.status === 200));
   assert.deepEqual(
     requests[3],
     Array.from({ length: 64 }, (_, i) => [(i + 64) / 100, 1]),
   );
   assert.deepEqual(
-    json(recovered).results,
+    recovered.flatMap((response) => json(response).results),
     Array.from({ length: 130 }, (_, i) => ({ ellipsoid: i / 100 + 100 })),
   );
   assert.equal(requests.length, 4);