I can't repro reliably but if an AssignProcedure or UnassignProcedure is a subprocedure of an Enable/Disable and for whatever reason the parent decides it needs to rollback – can't get an entity lock – it will ask the subprocedures to rollback. UP and AP don't support rollback on all steps. For steps where not supported, we have been throwing a UnsupportedOperationException.... The Framework reschedules the rollback. And so on filling logs and Procedure WALs.
Instead just note no rollback supported and intervention may be needed (until we to to 2.2 when AP/UP go away).