I accepted him on board on the ship and he did not join the party. I said welcome aboard but he did not join. Is this a known bug? 

I accepted him on board on the ship and he did not join the party. I said welcome aboard but he did not join. Is this a known bug? 

 

Known bug and the trigger seem to be asking about other conversation choice before picking "Welcome Abroad". He should appear the Deadfire Fort at the south door when you are at the exterior side of the map. That's where I got him when he suddenly went poof.

Yeah, game thinks you didn't ask him to join so he instead ends up in his default location which is skulking around in front of the doors to dungeons in Deadlight Fort