The problem is at the end of the rename operation, when we force a refresh on both collections: from and to. The issue is that the asynchronous work submitted by the the refresh of the from collection,which is a dropCollection, conflicts with the refresh of the to collection.

You can find a detailed description of this problem here.

As part of this work we should also remove this if-stmt. This code is not needed anymore since we already have a proper cleanup phase.