Close the game down, load it back up and load a previous save, what worked for me.
This is probably because theres some action we did ingame which cut the "chaining to other teammembers" and you reloaded without really knowing which action it was which did bug your teammember and therefore probably loaded just the right savegame where everything was ok. Lucky you.
I cant even remember anymore which savegame it was on my bugged out Shadowheart, where she was totally compliant to follow anywhere

Now i have to run around with her as teeamleader which really annoys me. What with all those events you run into which start conversation or some events....
This is making me reloading much more often now. To have just the Character as lead for such events.