Cobalt 7 of 9 duel pistols promo in zen store

Hope this isn’t a duplicate post. I looked back through a few pages of posts and did not see a post about this. I noticed that I cannot upgrade the weapons. On previous cobalt sets I have been able to to upgrade them such as the Ba’ul weapons. The duel pistols have the upgrade option and it even puts the weapons in the upgrade function in the game but I used several universal upgrade tokens to try and upgrade them but the weapons will not upgrade. Is there a fix for this?