Re-verified f2de8fe (hashes, walk 5,642/5,642, far topology 0 diffs vs CPU and
WARP, GPU survival). The remote LOD3/4 band was a direct-GPU coverage loss
(overlapping pixels identical, surface pieces missing, e.g. (6,2,0,lod3));
LOD3/4 now mesh on CPU, root cause in the GPU route still unidentified.
A minimal first-submit repro (pools, first-touch dispatch, device flags) did
not reproduce the 2.4 s stall. Whole view: CPU 1.438 s vs GPU 4.704 s median.
Crossing probe overflowed GPU output slots: no valid crossing latency.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ