Egbert, I'm sorry, I can't find Teri's dialogue - she shouldn't have anything after the barbarian camp.
Maybe I should look more.
For Korin, I think it's a Korin-Holvir dialogue, and I have no idea why it went wrong, but try and set SetGlobal("O#NPCHolvirKorin10","GLOBAL",1000) or something like that - should lock the dialogue.