How to reproduce the bug:

• Place an armor stand in your world
• Type this command in chat
  /execute as @e[type=armor_stand] at @s run tp @s ~ ~ ~ ~90 ~
  The armor stand is supposed to rotate 90 degrees, and that happens!
• If you keep typing that command though, you will notice that, at a certain point, it will NOT work anymore and the armor stand will not rotate. If after that you try it again, the armor stand will skip a 90 degree rotation and will rotate a full 180 degree!

What it seems to me is that the armor stand always rotates, but his animation for some reason is not always updated and falls behind!

Note:

• When the command didn't work I went in gamemode 3 and clicked on the armor stand to spectate him and I noticed it actually put me in the rotation where the armor stand was supposed to be! This means that it's only a visual glitch, the armor stand is actually in the right location!