Black landscape's chunks in UE5.4 after applying a material instance

Hi. I used the brushify’s landscape material and then I wanted it to be a material instance so I could edit it in my scripts at runtime.
After applying the landscape material instance to the landscape, it became completly black and shiny.

Before:

After:

I have also tried to recreate the problem in another project and I made a very simple landscape material but it works perfectly. Probably I am missing something in the complexity of the brushify’s landscape material.

Any idea on how I can fix it or is there any way to correctly switch form a landscape material to a landscape material instance?