I've added spoiler tags to your text as there are many new people now playing the game for whom even early access content might be spoilery.
In my playthrough, I also have no cub but my problem is different as
I didn't kill the mother (successfully roared at her) and the cub was at the goblin camp. I persuaded them to let it go, and dealt with the goblin leaders, but it's now about three or four nights later and still no cub, and I'm about to head to Grymforge. I didn't kill the goblins out in the courtyard after the leaders as I escaped through the Underdark, but I don't think that made any difference in EA.
