I had this same problem and tried everything I could come up with and everything you guys came up with; Found this youtube video https://www.youtube.com/watch?v=hiRiIgv5mA4 tho. And it helped me. I just let the followers and morrigan do as they pleased. I thought I needed a follower to turn the lever but apparently not 🙂
The best advice i can give for this issue is to take it slow, and go one step at a time, don't run through the tiles even if you know exactly what you're doing. It took me about an hour to calm down after this happened 3 or 4 times. It worked right away. I don't know if this is a real solution, but i guess it is worth a try?
In my personal experience, the followers never activate tiles if you don't give them any commands. Telling them to hold position may actually work against you.
