With over-creation fixed, the incidents that remain are readable enough to judge, and the ones that still do not make sense all fail the same way. A content-free call attaches to the single active incident on its talkgroup if that incident has been idle under tg_dispatch_thin_idle_minutes, and at 10 minutes that is long enough for the channel to have moved on to something else. In the 00:30Z dump a "72 at Holland Station" incident absorbed a Grand Central train-crew meet 9.6 minutes later, and a status check absorbed a records lookup at 9.7. Being the only candidate is not evidence. It means the channel was quiet, which is exactly when guessing is weakest -- the single-candidate rule was meant to avoid picking wrongly among several, not to license a match no other signal supports. Every correct thin attach in that dump was <= 3.4 minutes idle and every wrong one was >= 8.2, so 5 separates them with room on both sides. Real back-and-forth is unaffected: it runs through the 30-second tier-1 path, and the observed conversational replies sit near zero. Tests pin both sides of the new boundary at 4.9 and 5.1 minutes so a later change to this number has to be deliberate. 23 pass. Also corrects a DEFERRED.md entry written earlier today. It claimed nothing ever closes an incident that goes quiet; summarizer.py has run a stale sweep at incident_auto_resolve_minutes (90) the whole time. The 37 open incidents were caused by over-creation, not by a missing sweeper, and 90 minutes may be fine now -- worth rechecking on a fully post-fix dump before changing it. No new environment variables: tg_dispatch_thin_idle_minutes is a config.py default and is not templated into any .env, so CI deploys this without an ansible run. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>