The collMod coordinator commits the new timeseries options to the global catalog before broadcasting the modification to the shards, but only takes the critical section on the shards that own chunks. A shard holding a local copy of the collection without owning any chunk is therefore left unprotected during that window, so a secondary reading at its own lagged timestamp inside it sees the two catalogs disagree and reports a CollectionOptionsMismatch. This suppresses the timeseries options comparison on delayed secondaries when the global catalog entry read at the same snapshot has allowChunkOperations set to false, which marks an in-flight DDL and strictly contains the divergence window.