I put in a ticket for this a few days ago and provided a save file today with the bug occuring. They have been able to confirm it and have forwarded it to the dev team to look into.
It appears to be centered around a random character in your party who is causing the problem. Saving and reloading does NOT fix the problem. It can happen in single and multiplayer campaigns - had it happen to one of my teams 8 hours in when we got to the Grymforge.
It's frustrating, but they are aware of it.
