Based on this documentary, the Yeti didn't come into the mountain until after it was completely built? Unless the documentatory is just out of sequence? It seems to me they put this thing in with the mountain completely built.
This dubunks a theory that they "can't" fix it because they've have to take the mountain apart. I've always said that seems wrong and anything can be done with the will to actually fix it properly.
I think they left an opening in the wall to fit the yeti in when building the attraction and then 'walled it in' once it was fitted? If so they would have to remove part of the mountain to take it out?