Yes, Dogshit. Not even Accountwide.
There is a plate tierset with a certain model and there are non-set items with the same model.
The tierset has a class restriction and non-set items dont. This means, if you want to get the model on all your Chars, you have to get the non-set version.
This, in theory, is fine. But it's bugged.
If you get the tierset on the right class, you will unlock it. If you log onto another class with the same armortype, the skin for this item will be grew (if there is anychance to obtain it) and blizzard will show the only source to get this item, which means: Get the non-set version.
But if you get the non-set version, the tooltip on this item, won't tell you, that you have to equip it to learn it. (If it's boe, and this is the case, quite often). This means, you have to know, that you still need the skin.