diff --git a/CHANGELOG.md b/CHANGELOG.md
index 02af2c6e2..b51d8c8e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,10 @@ of current runtime behavior, see [`docs/CURRENT-STATE.md`](docs/CURRENT-STATE.md
 
 ## [Unreleased]
 
+- Unchanged local infrastructure overlays no longer sustain idle rendering.
+  Ground samples wait for visible terrain to settle and cannot place a marker
+  below its loaded surface; roofs and valid below-sea-level heights are retained.
+
 - Datacenter and dam marker stems use bounded, zoom-dependent active sets with
   stable selection during camera motion. Close-up stems scale to the actual
   camera distance; source totals and submarine cables remain unchanged.
diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index a4f1fe706..8e7d65622 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -8,6 +8,11 @@ and 420 below 200 km. Selection favors existing label priority and nearby
 features, retains stable choices across small camera movements, and refreshes
 during continuous motion. Disable/re-enable resets selection cleanly.
 Close-up stem sizing uses camera-to-feature distance without a 5 km minimum.
+Unchanged overlay entries do not request another frame; moved positions,
+changed membership and re-enabling still publish. Ground sampling waits for
+visible globe tiles to settle and uses valid loaded terrain as a floor while
+retaining rooftop and below-sea-level elevations. A hidden globe does not
+constrain photoreal geometry, and retry work remains bounded.
 The submarine-cable renderer is unchanged. These limits bound active stem work;
 they do not reduce the materialized entity count or establish an FPS gain.
 
diff --git a/scripts/qa-infra-lod.mjs b/scripts/qa-infra-lod.mjs
index be78b2c89..5be19fe64 100644
--- a/scripts/qa-infra-lod.mjs
+++ b/scripts/qa-infra-lod.mjs
@@ -296,12 +296,27 @@ try {
 
   // ── parked-idle honesty: the LOD walk must not force continuous render ─
   await new Promise((r) => setTimeout(r, 4_000));
-  const idle = await page.evaluate(() => new Promise((resolve) => {
-    const scene = window.__godsEyeView.viewer.scene;
-    let renders = 0;
-    const remove = scene.postRender.addEventListener(() => { renders += 1; });
-    setTimeout(() => { remove(); resolve({ renders }); }, 5_000);
-  }));
+  const idle = await page.evaluate(async () => {
+    const { getRenderGovernorDiagnostics } = await import('/src/renderGovernor.js');
+    return new Promise((resolve) => {
+      const scene = window.__godsEyeView.viewer.scene;
+      const startedAt = Date.now();
+      const tilesLoadedBefore = scene.globe.tilesLoaded;
+      let renders = 0;
+      let framesWithPendingTiles = 0;
+      const remove = scene.postRender.addEventListener(() => {
+        renders += 1;
+        if (!scene.globe.tilesLoaded) framesWithPendingTiles += 1;
+      });
+      setTimeout(() => {
+        remove();
+        const governor = getRenderGovernorDiagnostics();
+        resolve({ renders, tilesLoadedBefore, tilesLoadedAfter: scene.globe.tilesLoaded,
+          framesWithPendingTiles, mode: governor.mode, holds: governor.holds,
+          requests: governor.recentRequests.filter(request => request.at >= startedAt) });
+      }, 5_000);
+    });
+  });
   report(CONTROL
     ? 'parked idle, control (postRender fires / 5s)'
     : 'parked idle with infra ON (postRender fires / 5s)', idle);
diff --git a/src/data/localGeojson.js b/src/data/localGeojson.js
index aba4b7ee5..b32fef1f7 100644
--- a/src/data/localGeojson.js
+++ b/src/data/localGeojson.js
@@ -225,6 +225,11 @@ export function createLocalInfrastructureOverlayPublisher({
   let visible = false;
   let published = false;
   let destroyed = false;
+  // Local entries have immutable metadata and a mutable Cartesian position.
+  // Snapshot coordinates: retaining only the entry reference would miss a
+  // stem tip moving in place. Republishing an unchanged cohort invalidates
+  // the host and can sustain a render loop when frames exceed the 450 ms walk.
+  let lastPublication = null;
   const sourceOptions = {
     cohortLimit: LOCAL_OVERLAY_COHORT_LIMIT,
     collisionCapacity: LOCAL_OVERLAY_COLLISION_CAPACITY,
@@ -239,7 +244,18 @@ export function createLocalInfrastructureOverlayPublisher({
     },
     publish(entries) {
       if (destroyed || !visible) return;
+      if (lastPublication && entries.length === lastPublication.length
+        && entries.every((entry, index) => {
+          const previous = lastPublication[index];
+          return entry === previous.entry
+            && entry.position?.x === previous.x
+            && entry.position?.y === previous.y
+            && entry.position?.z === previous.z;
+        })) return;
       host.setEntries(sourceId, entries, sourceOptions);
+      lastPublication = entries.map(entry => ({
+        entry, x: entry.position?.x, y: entry.position?.y, z: entry.position?.z,
+      }));
       published = entries.length > 0;
     },
     hide() {
@@ -248,6 +264,7 @@ export function createLocalInfrastructureOverlayPublisher({
       if (visible) host.setVisible(sourceId, false);
       visible = false;
       published = false;
+      lastPublication = null;
     },
     destroy() {
       if (destroyed) return;
@@ -255,6 +272,7 @@ export function createLocalInfrastructureOverlayPublisher({
       if (visible) host.setVisible(sourceId, false);
       visible = false;
       published = false;
+      lastPublication = null;
       destroyed = true;
     },
   };
@@ -897,6 +915,8 @@ function sampleLocalGroundHeight(viewer, record, now) {
   if (record.groundSampled || !viewer.scene.sampleHeightSupported) return false;
   if (now - record.lastGroundSampleMs < GROUND_SAMPLE_RETRY_MS) return false;
   record.lastGroundSampleMs = now;
+  const globe = viewer.scene.globe;
+  if (globe?.show && globe.tilesLoaded === false) return false;
   let sampled;
   try {
     sampled = viewer.scene.sampleHeight(record.carto, [record.entity]);
@@ -904,6 +924,14 @@ function sampleLocalGroundHeight(viewer, record, now) {
     return false; // tiles not ready; retry on a later bounded update
   }
   if (!Number.isFinite(sampled) || Math.abs(sampled) > GROUND_SAMPLE_MAX_ABS_HEIGHT_M) return false;
+  // A coarse scene-depth sample can lie below the terrain already loaded by
+  // the visible globe. Keep that terrain as a floor while allowing roofs and
+  // valid below-sea-level elevations. Photoreal scenes hide the globe, so its
+  // inactive terrain must not constrain their geometry.
+  const terrainHeight = globe?.show ? globe.getHeight?.(record.carto) : undefined;
+  if (Number.isFinite(terrainHeight) && Math.abs(terrainHeight) <= GROUND_SAMPLE_MAX_ABS_HEIGHT_M) {
+    sampled = Math.max(sampled, terrainHeight);
+  }
   record.groundSampled = true;
   record.groundHeight = sampled;
   Cesium.Cartesian3.fromRadians(
diff --git a/src/data/localGeojson.test.mjs b/src/data/localGeojson.test.mjs
index 3b543954a..0fd84f24d 100644
--- a/src/data/localGeojson.test.mjs
+++ b/src/data/localGeojson.test.mjs
@@ -314,6 +314,33 @@ test('local overlay publisher owns add/remove/visibility lifecycle and becomes i
   assert.deepEqual(calls[7], ['visible', 'local-datacenters', false]);
 });
 
+test('slow parked frames do not keep republishing the same local overlay cohort', async (t) => {
+  const env = await createRealLocalLayerHarness();
+  const clock = installFakeClock(t);
+  t.after(() => { env.layer.destroy(env.viewer); env.cleanup(); });
+  const publications = () => env.hostCalls.filter(([type]) => type === 'entries');
+  env.preRender.raise();
+  assert.equal(publications().length, 1);
+  assert.ok(publications()[0][2].length > 0, 'the initial cohort must be populated');
+  for (let i = 0; i < 6; i++) {
+    clock.advance(1_000); // Every slow frame passes the 450 ms source throttle.
+    env.preRender.raise();
+  }
+  assert.equal(publications().length, 1,
+    'unchanged publication invalidates the real host and requests another slow frame');
+
+  const camera = env.viewer.camera.positionWC;
+  env.viewer.camera.positionWC = Cesium.Cartesian3.add(camera,
+    new Cesium.Cartesian3(10_000, 0, 0), new Cesium.Cartesian3());
+  env.moveEnd.raise();
+  env.preRender.raise();
+  assert.equal(publications().length, 2, 'changed stem positions must still reach the host');
+  env.layer.disable(env.viewer);
+  await env.layer.enable(env.viewer);
+  env.preRender.raise();
+  assert.equal(publications().length, 3, 're-enable must republish after clearing the host');
+});
+
 test('real layer disable clears its published host entries and balances settle listeners', async () => {
   const env = await createRealLocalLayerHarness();
   env.preRender.raise();
@@ -683,6 +710,44 @@ function governorReasons() {
   return getRenderGovernorDiagnostics().recentRequests.map((entry) => entry.reason);
 }
 
+test('ground sampling waits for visible globe tiles before caching a height', async (t) => {
+  const env = await createRealLocalLayerHarness({
+    sampleHeightSupported: true, sampleHeight: () => 117,
+  });
+  const clock = installFakeClock(t);
+  t.after(() => { env.layer.destroy(env.viewer); env.cleanup(); });
+  env.viewer.scene.globe = { show: true, tilesLoaded: false, getHeight: () => 117 };
+  setCameraAltitude(env, 20_000);
+  env.preRender.raise();
+  assert.equal(env.sampleCalls.count, 0, 'streaming terrain must not become a permanent coarse sample');
+  assert.ok(Math.abs(baseHeightM(env)) < 0.01);
+  env.viewer.scene.globe.tilesLoaded = true;
+  clock.advance(2_100);
+  env.preRender.raise();
+  assert.equal(env.sampleCalls.count, 1, 'the existing retry must sample the settled scene');
+  assert.ok(Math.abs(baseHeightM(env) - 117) < 0.01);
+});
+
+for (const [terrainHeight, sampledHeight, expectedHeight, globeShown] of [
+  [117, -2238, 117, true],
+  [-400, -410, -400, true],
+  [117, 180, 180, true],
+  [117, -20, -20, false],
+]) {
+  test(`ground sampling respects terrain ${terrainHeight} and geometry ${sampledHeight} with globe ${globeShown}`, async (t) => {
+    const env = await createRealLocalLayerHarness({
+      sampleHeightSupported: true, sampleHeight: () => sampledHeight,
+    });
+    installFakeClock(t);
+    t.after(() => { env.layer.destroy(env.viewer); env.cleanup(); });
+    env.viewer.scene.globe = { show: globeShown, getHeight: () => terrainHeight };
+    setCameraAltitude(env, 20_000);
+    env.preRender.raise();
+    assert.ok(Math.abs(baseHeightM(env) - expectedHeight) < 0.01,
+      `base ${baseHeightM(env)} must respect the visible terrain without flattening roofs or below-sea-level terrain`);
+  });
+}
+
 test('a failed ground sample schedules the retry frame the idle governor would never produce', async (t) => {
   const env = await createRealLocalLayerHarness({ sampleHeightSupported: true });
   _resetRenderGovernorForTest();
diff --git a/src/data/localGeojsonLod.test.mjs b/src/data/localGeojsonLod.test.mjs
index fcbdc754f..c492b0404 100644
--- a/src/data/localGeojsonLod.test.mjs
+++ b/src/data/localGeojsonLod.test.mjs
@@ -58,7 +58,7 @@ test('infraLodBudget band boundaries are inclusive at the lower edge', () => {
   assert.deepEqual(infraLodBudget(INFRA_LOD_REGIONAL_HEIGHT_M - 1), { activeLimit: INFRA_LOD_ACTIVE_MAX });
 });
 
-test('infraLodBudget treats non-finite / negative height as the global (cheapest) band', () => {
+test('infraLodBudget uses the global band for non-finite height and clamps negative height to zero', () => {
   assert.deepEqual(infraLodBudget(undefined), { activeLimit: INFRA_LOD_ACTIVE_MIN });
   assert.deepEqual(infraLodBudget(NaN), { activeLimit: INFRA_LOD_ACTIVE_MIN });
   assert.deepEqual(infraLodBudget(Number.POSITIVE_INFINITY), { activeLimit: INFRA_LOD_ACTIVE_MIN });