Final agency action and res judicata


So the SJC issued another 80C decision, and obviously I must discuss it (it's like an addiction).  In Tomer v. MHRC, the Court held that a Maine Rights Commission decision in which the Commission ruled that it lacked subject matter jurisdiction over a claim (here because the issue was an internal tribal matter) is not final agency action, and, therefore, appealable, because the Commission has no adjudicatory function when reviewing a discrimination claim:

This is all logical, and the only thing I am pondering is what will happen next.  The SJC notes that the plaintiff can file a civil suit.  If he does, the tribe will no doubt argue lack of jurisdiction again.  If so, is the Commission's ruling that this is an internal tribal matter res judicata?  The SJC did not review that question on the merits - instead, it found it could not review what the Commission did, because it was not final agency action.  There were indicia of due process at the Commission level in making the internal tribal matter decision, which ordinarily give agency decisions res judicata import.  But if you cannot appeal an agency decision, does that mean that decision cannot be used as res judicata, even if those other indicia are there?  Maybe the internal tribal matter ruling for the purpose of determining the Commission's own jurisdiction is sufficiently divorced from the issue whether its an internal tribal matter for the purpose of any state court jurisdiction, so that there is no res judicata implication.  Or maybe there are simple answers to these questions in the Restatement.  But it's still (to me) an interesting potential conundrum.