I have a handful of armor stands in my realm that keep "resetting" their pose, specifically switching to the last pose in the sequence. The affected stands are all resting on (or pushed up against) trapdoors, but there are no other redstone components nearby that might be powering the stands.

I'm not sure what prompts the reset; I haven't been able to reproduce it consistently with leaving/joining the realm or leaving/returning to the area. But I find myself fixing the poses multiple times a day, so the issue definitely happens frequently, though always when I'm away from the area.