Originally Posted By: Jerakeen
This sounds like one of the Shadowwalker abilities, specifically Cunning Decoy. The real Shadowwalker leaps away, leaving a fake in his place. I found this to be a bit buggy in the Mac version too, but not game-breaking. Could this account for what you're seeing, Mitcian? I don't think it explains Jt's problem, since (s)he doesn't mention the shade reappearing.
I highly doubt it. I have started eexperiencing similar problems with other NPCs in the ggame usually when they are somehow involved in a quest and combat. They perform an ability then no longer move before despawning after a few turns or suddenly getting one hit killed from full health. After that I'm usually stuck on the quest.