Question [Avatar mask] generic transform mask not animating

Hey,
I've got a 3d character model, custom rigged by creator (cannot change it), I created animations in mixamo, with the base animator layer, everything works fine with just the base layer. (I animate through code with a fish-net network animator).

I then proceed to add a generic avatar mask and select all the bones, when I trigger the animation, it does not animate the 2nd layer (max layer weight), but the base layer animations do play. Now if I remove the avatar mask, it plays the 2nd layer animation but not the base ones.

How can I setup the avatar mask?