Painted Landscape Tile Specular/Roughness mismatches unpainted tiles

My setup is simple. I have 3 Material Functions “Grass” “Rock” and “Path” each with diffuse/normal/ORM maps plugged into a Material Attributes output node. Inside my terrain material I blend Grass and Rock Material Attributes with a world aligned Blend, and then blend this through a Layer Blend node with Path. Layer Grass is given Preview Weight 1, so it is the default layer. The Landscape material is in Material Attributes mode, Shading Model = Clear Coat. Just in case, here’s screenshots of each of the three material functions and the main terrain material. All texture-sample sources are set to Shared:Wrap Imgur: The magic of the Internet

In editor any tile I have not painted with landscape layer paint, Grass looks fine, while Rock looks too shiny, like it’s roughness is 0. Any tile I have painted with Path, all three materials look faded out, as if they have a uniform Roughness 1. When I set render mode to ‘Unlit’, the painted tiles also appear washed out. When viewing specular, unpainted tiles appear correct while painted tiles appear full bright. When viewing roughness everything looks correct. I cannot view the clearcoat buffer, so I do not know how to judge if it is at issue here. UPDATE: Switching the material from Clearcoat to Default Lit does not clear up the issue, so I am ruling clearcoat being at fault out at this time.

If I bypass the Layer Blend with any of the three Material functions, they appear on the landscape as expected. If I connect just the Grass/Rock world-aligned blend, it looks as expected.

Here is an image of the issue in-editor, at the top you can see the rock is shiny as if roughness=0. Imgur: The magic of the Internet

Further discoveries: Tiles that have been painted with Path lose all their tessellation/displacement.

Adding a scalar=1 to Path’s specular input fixes Rock appearing shiny, and lets the roughness and specular of painted tiles appear normal, but Path looks brighter than it should when compared to when it’s by itself: Imgur: The magic of the Internet