DTM Deadlock on Abort with Region Closing

When doing system setup for expansion testing on a system with moderate transactional entry (TPC-C-like transactions, but at a relatively low rate), I had a region that got stuck in transition.

DTM developers looked at it (wasn't sure whether it was an operational issue or a bug that caused it). During that research, they determined that there is the potential for a deadlock in cases where transactions are aborting as the region is closing. Aborts are blocked as part of blocking new transactional activity. So the region can't close if there's a transaction there but it's not letting the abort through to clear the transaction.