I'm glad I could help GalexMystra!
I think knocking him out is probably the most common reason for him not to show up. The game often register knock-out as a kill, and the cub is not temporarily hostile (and I have had the game count temp hostile knock-out as kills too!) so he will effectively be dead in that scenario.
And is moving to Act 2 before resolving the mother/cave issue also a reason for losing out on the cub? If someone knows I would love for them to chime in.
