debug_try_anchor asks validate_block directly at the capture-proven offsets. Both 119-vert twin buffers are accepted by both twins (so the correct block lost the first-match race, and a distinct assignment fixes it); the drawn 51-vert bridge buffer is accepted by both bridge resources; eng_02_l's proven offset is rejected outright, even with the pad widened to 64 -- a validator gap, not a selection one. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>