Duel at end of The Cairn Docking Bay

[Swocha]

At the end of this level, there should be a dual between Desann and Luke. On my system, only Desann shows up (no Luke) then the dual fails to complete (obviously) and the game won't progress. I tried to npc spawn luke as a test and, sure enough I got an error. He showed up during the earlier level in the shuttle bay (can't recall the name) but now he's MIA. Any suggestions? I'm on Os 10.2.2.