I have several AmberForestTown building assets from the Fortnite library in my scene. Their materials are layered providing a different inside, outside, and trim. I needed to remake some of the wall to tighten some collision shapes. Upon copying the material of the FN asset onto the imported mesh the texture looks perfect in UEFN, but it does not show up in the actual game. Also upon saving, closing, and reopening it does not remain in UEFN. I assume this has to do with the read-only nature of the FN asset instance, but is there anyway to use these more complex materials as they appear in the original FN assets?
Maybe try creating a material instance from the FN material you are trying to reuse. And then use the instance on your custom assets.
The material seems to be in a folder called Engine/Transient and any time I make an instance of it it gives me a blank instance or if “material constant from base material” a weird cloud like texture.
I have had this same issue myself and would like to know if it can be worked around.
Did you ever find a fix?