Socketable Stashtab Upgrade unavailable

The Upgrade button states I should complete "Treasures of Utzaal" in act 3.
First of all I have completed said quest in both normal and cruel difficulties.

Second... WHAT!?! I get to pay for a "upgrade" feature and storage option but I require to unlock it after paying for it? I honestly understand it if this was a only-for-the-first-time deal like anoints with oils in PoE 1 blight (since you didn't have acces to Cassia). But this is a simple upgrade feature that I would be able to access if I used the Reforging feature unlocked elsewhere in the game. These 2 quests are unrelated and are clearly not a requirement to use the button as I still can't use it but I can Reforge. Please make this make sense? Also how do you release a stash tab that is broken? No one checked if it worked?