No longer able to change appearance of TR weapons to the new crafted weapons

A few weeks ago I made myself a new TR to take advantage to the Recruitment event, and got myself a set of weapons and transmuted them to the "Steel Poignard". Over the weekend here I went ahead and upgraded my weapons to a set of masterwork ones and it now appears that you cannot transmute them (or any other Tr weapons it seems) into the "Steel Poignard" model. I tried a few other of the crafted weapons and you cannot change appearance to them either. This worked fine a few weeks ago, so something has changed in that time that no longer allows these weapons to be used for transmutation (which really is one of the primary advantages of the crafted weapons).