I installed the new beta for MG3 Hex AUv3 (macOS) today. After a brief test, I could confirm that it functions as expected in Logic Pro (and also Reaper).
However, I’ve noticed that in Live 12 and Blue Cat Audio’s Axiom 2 and PatchWork, the GUI sometimes draws when it’s first launched, but if it’s closed and reopened, it always comes back with a blank rectangle. In Axiom, it doesn’t even draw if you directly instantiate it, but usually it will draw the very first time the plug-in is loaded in a user preset, then it goes blank when you hide/show the plug-in.
Considering that it works perfectly well in Logic Pro and Reaper, I guess it might be an individual DAW implementation of AUv3 issue, but I thought it was worth pointing out just in case it was a bug.