Nightrunner gear parts for transmog don't work

[lone sequoia]

It is not about outfit toggle, i am familiar to that !
Bought the nightrunner bundle, because we got the gear parts of the outfit for transmog.
But when I try to use them for transmog, as soon as back in the menu, it shoes the actual original gear you wear and not what you want it to look like.
Please try yourself and lmk if there is any solution, ty