I'm running into a weird bug. If NPCs trigger dialogue followed by combat the combat won't happen. Regular NPCs attack just fine but there seems a problem with those that have to give speeches not turning hostile. This happened several times in the swamps near Fort Joy. The first was Wendigo, who gave her speech and then just stood there. So we attacked her till she initiated combat.
All other combat works fine, Arena, rescuing Gareth, Fort Joy guards when you have no collar, undead in the swamps etc. Just any NPC that gives a speech doesn't trigger combat.
I'm playing 4 player coop if that matters. Couldn't find but one unanswered thread about this bug.