So spoilers obviously.

I see the owlbear cub at the goblin camp.
Make him my friend but he is afraid to leave because of the goblins there.

So I decide to go inside the temple, free Halsin and kill the leaders one by one and then clearing the courtyard.

But the Owlbear cub is gone!
What happened.

Am I seriously supposed to have hindsight knowledge that the cub disappears if I kill the leaders from the inside?