CAAF rules on the merits at the petition stage

In United States v. O'Neal, __ M.J. ___, No. 08-0024/AR (C.A.A.F. Jan. 15, 2008) (summary disposition), CAAF took the fairly unusual step of ruling on the merits of a claim at the petition stage before plenary briefing.

CAAF granted review of this issue:

WHETHER THE MILITARY JUDGE ERRED BY FAILING TO REOPEN THE PROVIDENCE INQUIRY IN ACCORDANCE WITH UNITED STATES v. PHILLIPPE, 63 M.J. 307 (C.A.A.F. 2006), WHEN FACTS ELICITED DURING APPELLANT’S UNSWORN STATEMENT RAISED THE POSSIBLE DEFENSE OF MISTAKE OF FACT AS TO AUTHORITY TO LEAVE.

But then, rather than ordering briefs or remanding the case to ACCA, CAAF ruled immediately: "The decision of the United States Army Court of Criminal Appeals is reversed as to Specification 2 of Charge I and as to the sentence, but is affirmed in all other respects."

Can one of our Army lurkers please fill us in on what happened. Did GAD concede error at the petition stage? And what were the precise facts giving rise to this outcome? I couldn't find ACCA's opinion online.