Hrmm, I think I found the root of the findByPK(NULL) change, here: http://sourceforge.net/tracker/index.php?func=detail&aid=767716&group_id=22866&atid=376685 (Bug #767716). Took all morning to track this one down.
But that's just one of many errors....
Afair, Alex rewrote the ejb-ql parser between 3.2.1 and 3.2.2.
But you are right, finders are supposed to return RemoteException or Finder Excption where IllegalArgumentException is no child of.
You might rise a bug report.