Edit: I found him again - it seems, now that he leaves his tent to Minthara, he sometimes wander to the outer parts of camp.
During my playthrough, I didn't realise you could gain Minthara as a companion until it was too late, so that couldn't cause issues for me. (I played a githyanki necromancer who turned the entire Goblin Camp into an abattoir without asking further questions.) Such dynamic behaviour may be at the core of the issue. Back when I reported the camp animation bug, I also read his special wild shape was causing trouble. I can't remember which, though.
