So I just came back to the game a few weeks ago and have been levelling some new alts, etc. I noticed this problem once when I first started, and just noticed it again while trying to heal a normal low level dungeon.
The tank kept “telporting” back and forth to the start of the dungeon, like two or three times a second, as if they were blinking in and out of existence. Constantly through the dungeon. At first I thought it was a graphics error, but their icon on the mini map was flickering between our current location and the dungeon entrance, spells being targetted at them were flying across the dungeon, and their Judgment and Avenger’s Shield abilities were sometimes normal and sometimes flying in from nowhere.
Not only that, they were almost impossible to heal because they were going in and out of range rapidly, so I had to keep pressing the healing skills until one of them landed while they were in range. I am using addons, but it seems unlikely an addon would cause a player and all the attacks at and from them to behave like that (but I’m no expert for sure). The tank never mentioned anything and no one in the party said anything either, and it was only that one player (and only one player, the tank again, the first time I saw it happen).
Is this a problem on my end, an addon problem, or something that occasionally happens now?