A sharded time-series collMod can leave shard participant critical sections held if it hits a non-retriable error after the kBlockShards phase.

CollModCoordinator enters the critical section in kBlockShards by sending _shardsvrParticipantBlock with ReadsAndWrites to shards owning chunks. It only releases that critical section later as a side effect of _shardsvrCollModParticipant in kUpdateShards, when the participant sees needsUnblock=true and calls ShardingRecoveryService::releaseRecoverableCriticalSection().

There is no dedicated ReleaseCritSec phase and no collMod-specific _cleanupOnAbort() path. If a non-retriable error occurs after kBlockShards but before all participant _shardsvrCollModParticipant commands successfully release their critical sections, the coordinator can abort. The existing non-retriable error handling resumes migrations, but it does not send an unblock command or otherwise release the recoverable critical sections.

Result: CRUD may remain blocked on affected shards even though the collMod coordinator has aborted.