I am not sure if this applies but I was under the impression that you reach the "burned down" state when you travel to Act 2, isn't it that way? You usually get a warning about leaving the chapter but there is a very convenient path into Act 2 from the Goblin Camp.
Hmm, Maybe that's the reason? I've unwillingly gone to act 2. After returning to the forest and the grove, normally when you jump the broken bridge, there should be a cut-scene with Voss and Laezel, but now nothing happens.
