Im using material functions to make the layer of the master landscape material, i made a first base material function and i maked instances of it as Desert and GrayBiome. The problem is that i can’t use another material in the landscape than Auto, because the chunk doesn’t load.
Try sculpting just a portion of that area.
There was an occasional bug like that in 4.x. Either painting or sculpting got it back to normal.
Beyond that, I have no other answer for you.
No, it doesn’t work.