The decisive probe (3cf6bcc) caught it live in ONE session: a 43-part
staircase entity (src=0x020003F2, healthy MeshRefs tZ=[0.35..15.15])
drew with cache=hit:3 restZero=3 - THREE batches belonging to a 1-part
entity - then under a different hint the correct hit:119. Two
compounding bugs:
1. interiorIdBase = 0x40000000 | (landblockId & 0x00FFFF00) resolved to
0x40YYFF00 for landblock keys 0xXXYYFFFF - the landblock X byte
DISCARDED. Every landblock in a map Y-row shared one id space:
Holtburg town A9B3's 9th interior stab == the AAB3 tower's spiral
staircase, both 0x40B3FF09. Fixed to 0x40000000|(lbX<<16)|(lbY<<8)
(the scenery 0x80XXYY## scheme).
2. The Tier-1 classification cache's #53 tuple key (EntityId,
LandblockHint) was fed the PLAYER's landblock at bucket-draw time
(RetailPViewRenderer.DrawEntityBucket fabricates its tuple with
ctx.PlayerLandblockId), so colliding ids from different landblocks
shared a key: whichever entity classified first under a hint won,
and the loser wore its batches all session (static fast path never
re-classifies). Also: bucket-hinted entries were never swept by
InvalidateLandblock(owner) - stale entries survived owner unload.
Fixed: ResolveCacheLandblockHint derives the hint from the entity's
owning cell (ParentCellId landblock, canonical 0xXXYYFFFF), falling
back to the tuple id for ownerless paths (outdoor stabs/scenery,
where the tuple IS the owner).
Explains the session-shaped repro exactly: town-login + run to the
tower hydrates/classifies town interiors first -> the tower staircase
cache-hits the town twin's batches (stairs missing/partial + a wrong
object near the floor - the "water barrel"); login-inside classifies
the tower first -> usually clean. meshMissing=0 / entSeen==entDrawn
both ways (everything draws, wrong batches). Likely also feeds #113's
distance-dependent phantom staircase (the town twin wearing the
tower's staircase batches).
3 new cache tests pin the collision contract + hint derivation.
Suites: App green / Core 1430+2skip / UI 420 / Net 294.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>