The first cut of the dungeon gate keyed expand on the per-frame insideDungeon
signal (CurrCell is a sealed EnvCell). Live, CurrCell momentarily resolves to
null mid-frame while the player stays put in the dungeon landblock, so the gate
flipped collapse→expand→collapse every few frames. Each expand re-streamed the
full 25×25 window; the unloads couldn't keep up (MaxCompletionsPerFrame=4), so
registered lights leaked to 212k and FPS spiked to single digits between the
~199 fps collapsed frames.
Fix: once collapsed, key the gate on the STABLE observer landblock, not CurrCell.
Stay collapsed while the player remains in the dungeon landblock (_collapsedCenter);
expand only when the observer actually moves to a different landblock (portal/
teleport out). CurrCell flicker no longer thrashes.
Regression test added (Collapsed_CurrCellFlickersToNull_SameLandblock_DoesNotExpand).
Build green; 60 streaming tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
d9e7dd65e9