EnterPlayerModeNow computed the initial cellId from landblock prefix
+ hardcoded low byte 0x0001 (outdoor sentinel) and passed only the
low 16 bits to PhysicsEngine.Resolve. When the server places the
player INSIDE a building (spawn cell id e.g. 0xA9B4015A indoor), the
sentinel forced the outdoor seed branch — for the first several ticks
CheckBuildingTransit hadn't yet picked up the interior cell (it
depends on the sphere overlapping the destination cell's BSP), the
player was classified outdoor, indoor BSP queries didn't run, and
exterior walls were passable until enough inward motion finally
promoted them.
User-visible symptom: "logged in inside the inn, ran out through the
exterior wall; ran back in and the walls now block."
Fix: use spawn.Position.LandblockId (the server's authoritative full
cell id with landblock prefix) when available; fall back to the old
sentinel only if the spawn record is missing (defensive — shouldn't
fire in live play since OnLiveEntitySpawnedLocked writes _lastSpawnByGuid
before EnterPlayerModeNow can possibly run).
1147 + 8 baseline maintained.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>