You want help from Bethesda this is not the place to ask, you contact Bethesda Support direct and see if they can help with the problem.
Did you actually put the beast in his pen? Or just rush off once you got back to the hall? And the chief talks about him anyway, did you go get the grass and bring it back, whether the journal told you to do it or not.
Yes, I make sure the beast is in the pen, I've stood there with him for 24 hours in game, and then "waited" for another 24 hours in real time. I've even brought 10 redgrass ahead of doing ANY of the chief quests, but this still won't activate it. I've even created a new save, gone to the island, and tried it, but it didn't work there either...