I'm having a similar issue. I replayed the previous chapter a number of different ways but still experienced the same out come. I am given two opportunities to talk Brenda down, then finally she shoots me. I can't see any other option or action to take
I also noticed that I wasn't awarded achievements for the first two chapters.
I really enjoyed the both parts of this game. It's a shame that this has left me with a somewhat sour experience, and the likelihood I'll have to wait a number of weeks until a patch is released is pretty disappointing.