When every pod disconnects at once (normal end of a multiplayer round), a failed send inside the PEER_DOWN fanout recursively drops that peer and mutates by_host mid-iteration -> RuntimeError -> THE RELAY DIES, taking the round reset and the matchlog uploads with it (live crash, first 3-player internet round). Iterate over snapshots. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>