It has been observed a failure on autosplit_setFCV_downgrade_from_60.js.

Looking at the logs, the following sequence may have triggered this invariant:

1. j0:s0:prim succesfully completes the shardCollection() of test10_fsmdb0.autosplit_setFCV_downgrade_from_60_1
2. j0:s0:prim gets downgraded to 6.0 (from now on, any new shardCollection() request will be served applying the V2 of the DDL coordinator.
3. j0:s0:prim starts donating a chunk of test10_fsmdb0.autosplit_setFCV_downgrade_from_60_1 and acquires the critical section for the collection
4. j0:s0:prim receives a second shardCollection() request for test10_fsmdb0.autosplit_setFCV_downgrade_from_60_1, which should be treated as a no-op;
   • being run as a V2 DDL, it needs to acquire the critical section before verifying that the command is equivalent to what has been performed on step 1
   • nevertheless, such acquisition is illegal due to step 3 - and leads to the invariant