In earlier patches I came across something similar but maybe not identical to this once at Grymforge and once on the cable car thingy on the Rosymorn map, when two of my characters plummeted to their deaths when it started moving but two remained on the platform with no issues, but each time when I reloaded the bug didn’t recur. That would have been on balanced mode.

Thanks for the reminder to be careful with moving platforms on honour mode, Zarrin, and I hope your party survives!

"You may call it 'nonsense' if you like, but I've heard nonsense, compared with which that would be as sensible as a dictionary!"