WFLY-7680 introduced the concept of lazy transaction inflow. The transaction is not associated with the thread unless the EJB invocation mode causes the caller transaction to be used (if present).
This may have caused a problem where transaction association does not function correctly when transactional operations are invoked via IIOP, though I do not have a good explanation as to why this would happen yet.
The significant participants in this process appear to be:
It's possible that there is some situation where the behavior of the invocation has changed due to the remote TX inflow interceptor being gone, which prevents the transaction from being associated with the thread until later than before. Or, this may all be a coincidence and the problem may be caused elsewhere.