While transferring Signature gear to your HUD, you get a message similar to this:

LULU Signature HUD whispers: LULU SigCollar (leather) [1.1.36] <23391> is an outdated version of the newer LULU SigCollar (leather) [1.1.39] in your HUD, and will NOT be transferred. Keeping your newest version instead. (Everything's fine, don't worry.)

But when you try to wear your gear, you are told you have no valid gear in the HUD.

To fix, try the reset and refresh method (skipping steps 2 and 3 of course).