Following HOT or Downtime patching mode, Workflow processes get stuck and / or errant. These Workflow processes cannot be fixed - even by issuing a Retry.
Workflow process definition is changed (upgraded or uploaded). Subsequently, a patch is applied in HOT or Downtime patching mode, as opposed to the Online patching mode as normally recommended on 12.2.x releases of EBS. Afterwards, processes are started (as when sales orders or order lines are created) between the time workflow was changed and the time patching was done may become stuck or errant. Even Retry will not progress these errant workflow processes.
For additional details and for Patch information, refer to Doc ID 2367541.1.