The flip killed the branch-toggle flap (one path, zero OutdoorRoot frames). It exposed two residuals now PROVEN via a live [bshell] probe, not guessed: (1) oscillation = the outdoor-node flood membership swings 1<->~13 building cells frame-to-frame, so the walls (EnvCell shells) blink; (2) see-through = EnvCell wall polys are single-sided for SidesType==CounterClockwise, so from outside you see their culled back. The ModelId building shells DO render (6/6 with mesh) but are a partial frame, not the walls — the skip-all-interiors experiment proved the walls are the EnvCell shells. Fixes identified (stabilise flood + build back faces) but not implemented; full do-not-retry list + open pre-flip-reconciliation question in the doc.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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