Bug: You can't close the in-game chat window if you are talking to an NPC.
Bug: I froze my co-op party member buddy, then teleported him. There was no falling animation, he just appeared in place, and then started walking in place.
The good news is that I did test to make sure that if the party split up and one went to activate the first star stone, and someone else did something else, it didn't break the game. The other person was either teleported immediately (even if in combat), or if in dialogue, the teleport waited until the dialogue was finished.
However, I should note that when I activated the Starstone while my partner was in dialogue, my source hunter was frozen in place (upright, despite the "downed" status), but I could freely control and move Jahan. When my partner left dialogue, it faded to black.