This scenario can cause catalog inconsistencies.

Transaction 1 creates collection B
Transaction 2 creates collection A
Transaction 2 commits
Transaction 1 creates collection A
Transaction 1 attempts to commit, and fails due to conflicting creation of "A".

The catalog inconsistency results because as we apply the commit of transaction 1, we register collection B in the catalog before finding out that collection A failed to be registered. We do not currently have rollback handling to roll back the registration of collection B.