As the title says Cull and User Alpha Bias is not working with MatPBR2Layers.
Cull on "None" still shows everything in the mask texture.
User Alpha Bias has no effect at all.
Cull and User Alpha Bias should first of all work as intended with other Material Classes e.g MatPBR2Layers and should also affect the MASK texture (Or these settings should show up at the Mask texture aswell).