Can't transmog off-hand or main hand

For some reason I can't apply transmog to my main hand or off-hand items. I was able to transmog my other gear but when i try to apply transmog to my tyrannical dagger or to grievious off-hand, nothing happens. I have even tried with different xmogs with no luck. Anyone else having this issue or knows a way to solve it?

Hi mate, I have the same problem on my priest, I want to transmog my off-hand and when I click "apply" button, nothing happens...So I dont know is it problem with my client or it is server bug.
Anyone have some idea?

Transmogrifying off-hands is bugged at the moment.

You can check the bug tracker and up vote for visibility.