I know this might be late to this problem but i had it happen to me all I did was go through the chat with her very slowly and your guy shouldn't glitch again I think
i did think doing that too but i didn't test it, maybe it's something with the dialogue going to fast if the player spam the key for dialogue, but the first time it did that to me i wasn't very fast, not slow either. But with what i did it was working for me even if I did go quiclky with the dialogue. But like i said maybe i was just a coincidence.