(At the time of writing, no released version is affected by the bug because the new coordinator is feature flagged).

SERVER-79491 introduced the acquisition/release of critical section on participant shards. The release is calling into the ShardSvrParticipantBlockCommand that is throwing if the critical section reason differs.

This can lead to hit an invariant in the same way described in SERVER-70167, with the difference that it could be hit on a participant node rather than on the coordinator node.

A possible solution would be to add a flag to the command indicating not to throw in case the reason differs.