If I leave and come back he'll say he thought I was bored and then I can have him talk about the mural successfully. Kind of strange. On an unrelated bug note, the first time I came across the crater at black mountain it had only one dead BOS solider and one centuar. After being highly irradiated and leaving the crater, I gave the power armor to Raul for safe keeping (since i was carrying too much) and it said he couldn't wear it. I saved the game at this point and resumed later. Raul no longer had the armor and for some reason a bunch of centaurs and an evolved centaur appeared all of a sudden. This and the 2nd BOS soldier (this one carrying the holotape) spawned in the crater.
That's as much info as I can provide, can't really duplicate the second scenario without re-doing the whole black mountain thing. Just an fyi when reporting bugs, one should try to duplicate it and outline the steps they took. Don't just say "OMG, so many things are stock in rocks! fix this!" since that isn't very helpful