When renaming a collection via an oplog entry, it's possible to hit this clause. That statement performs work in its own WUOW/transaction and commits separately to completing the rename.
Note this logic is not a bug in the sense that it would only manifest if crashing/restarting during initial sync were smarter than retrying from the beginning.
However, this splitting of transactions results in an untimestamped write on the catalog. Verifying that all (necessary) writes to the catalog are timestamped is easier if that's also true during initial sync. The motivation for this ticket is to add timestamp verification.