Just reporting a bug. I've seen other's with the same problem. Trashcan Carla's brahmin gets stuck on roof of the default workshop house in Sanctuary Hills. I am playing on PlayStation 4. This is a minor bug, but still annoying as this is a finished game...

Please fix in the next patch.

I noticed a similar issue with the brahmin spawning in houses and getting stuck in the doorways. Effectively blocking off the house and trapping everyone in it. AI and pathfinding are an utter disgrace in this game.

It may fixes itself after a time. (so just do other stuff, or quests and see late again)

Also try to interact with Carla if he comes to Sanctuary back, and after the completion of that conversation the pack Brahms may come off the roof.

Yeah, just run away to a different cell and come back later. Should work itself out. I've had dogmeat on a roof and that brahmin gets in all sorts of weird situations. Lots of the time it even gets on a different routine, Carla will be at Sanctuary and the brahmin will be at the diner or just out on the road somewhere wandering about.