DTS Audio Unlock: Unable to Complete Request

I’m trying to enable DTS audio on a family account. I have already purchased InFuse Pro on the primary account. When I click “Unlock for FREE” I get an app store window, within which I authenticate.

Then I get an “Item Already Purchased” Dialog, stating “A family member has already purchased this. You get it for free.”

I click ok, and then immediately get a “Unable to Complete Request” error.

This is with Infuse 8.3.2.