When I’m using my “Unity Legendary” in my “Head” slot it does not work for any spec.
In fact when I’m using my “Unity Legendary” in my “Waist” slot, it does work for every spec.
I tried relogging and changing covenants, but unfortunately it was not useful for me.
I dont know if it worked at the start, because in raids my unity effect wasnt noticable, but in mythic+ it is.