ZOS made some pretty significant changes to the API around equipment changes, probably since companion gear also needs to be tracked now. Someone who knows AlphaGear's code will need to go through and update it.
Personally, I decided to jump ship to Dressing Room. I have to say I miss AlphaGear's UI, but that's life sometimes I suppose.
I assumed it would be a difficult fix, but it turns out it's only a few lines. As noted by other posters below, Beartram uploaded a fixed version in the comments of the AlphaGear page.
It's been sort of working for me (and I hadn't known there was a fix). Changing gear or skills one line at a time has worked. Doing the whole loadout at once has not.