The first necromancer’s cosmetic prestige set has a nice blue cold glow over the shoulders and helmet in the store/shop.
Found it great because all the summoned skeletons have the same glowing blue/cold aura on their bodies by default.
Equipped in the game directly on the closet (transmog): It doesn’t work in game and the cold blue aura is not there. It works inside the closet most of the time and in the main menu / character selection screen. But not ingame.
EDIT:
Seems to be a shared world issue. In dungeons you can see the glowing armor effect. But not in town and not in the open world. → Shared world, where other player can see you.
Why would Blizzard hide the special prestige set effect in the shared world? There should be no real performance impact, when 5 of these “glowing” necromancer players are standing in town at the same time…