Black squares on lightmap

Here are my lightmap results and settings



Texel validity view


This section of the map is made up of modular assets from this pack https://fertile-soil-productions.itch.io/modular-racekart-track-hilly-terrain-theme. Can I get some help figuring out what's happening to cause these black squares and darkened trees?

I have tried:

• Increasing resolution to 20.
• Increasing Direct/Indirect/Environment samples to the 30k region
• Setting Backface Tolerance to 0. This removes the red from the Texel Validity view as expected but does not fix the underlying black problem.
• Checking that all the assets have UVs automatically generated.
• Toggling Directional/Non-Directional.

 

There a few but not to the extent that would cause such a big problem (I think?)



I fired up Unity this morning without making any changes to this scene and ran a bake again and this is what I'm working with now



This is what the lightmap looks like

 

I read this one yesterday and this is what prompted me to put the Texel Validity screenshot in my original post and report that I tried the Backface Tolerance set to 0 to no avail. Can I do anything about the mesh normals facing outwards if unity is generating the lightmap uvs? I will try to set the materials on these meshes to render both faces and report back later.