Two overlapping bugs on the iOS map. Mapbox reloads the style on its own schedule (projection transitions, tile errors, memory pressure) and that wipes every runtime source and layer, but my render-tracking state still thought everything was on screen, so the next loadTerrain skipped the work and the map went blank. Added an invalidateAllLayerState that clears all the lastRendered caches on style reload and re-triggers terrain load, plus the same reset on every camera jump (user location, search result, geojson fit, session bounds) so moving to a new area actually refetches. Also bumped the terrain bounding box limit from 0.5° to 1.5° because at zoom 8 the viewport was wider than the limit and queries were being skipped as "too large." Suspect there are more places that mutate the camera without resetting bounds, but this covers the ones users actually hit.