Using landscape layer blends with material functions?

I’m currently working in 4.18. Is it possible to use landscape layer blends with material functions? Like this?

Image

It allows me to do it, but once I try to paint, it seems to only passthrough the base color of both (everything else seems to reset to default). Am I doing something wrong, or is this not possible?

This image shows what is happening, if a landscape tile doesn’t have any layer paint info, it renders correctly; but if there is any paint weight of the second layer, the first layer “breaks”. You can see it here at a tile border.

Image