Rules out three listener-side suspects (subscribeId reuse,
MAX_STREAMS_UNI credit, SUBSCRIBE_BUFFER overflow) by code trace.
Identifies moq-relay 0.10.x's per-broadcast `serve_group` task
pool as the prime suspect — same root cause documented in the
2026-05-01 cliff investigation, surfacing here when the listener's
QUIC session straddles two publisher cycles for the same broadcast
suffix.
Documents what would confirm the diagnosis (Kotlin↔Kotlin
reproducer + flowControlSnapshot + packet capture) and the two
mitigation paths (listener-side: recycleSession on inner cycle,
trade ~500-1000ms more gap for cleaner relay state; relay-side:
upstream feature request already filed in cliff-plan follow-ups).
No production code change. Production audio rooms don't cycle
aggressively enough to hit this cliff in practice.
Claude
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