I also seem to have this problem. Pretty much anywhere higher than the Temple of Frost my Followers stop following and I can’t activate Transportory stones. Thralls will rubberband to me after I cross that distance threshold, but won’t follow, attack or move to a location.

And some weird behavior on the way to “the floe” entrance to the volcano from the icy slopes. Some of my thralls would run back down hill after teleporting to me. Almost like there was something to attack, but then they’d just stop at the foot of the mountain.

Once I’m in the Volcano, they teleport to me and just stand there. Refusing to move or attack anything. I can move the horse around, but that’s it. Won’t follow me when I dismount.

Edit: Its not just my thralls. Even enemies and wildlife won’t move or do anything.