Hi Eric. I imported your version no problems. However I couldn’t find any differences between our versions. I did another little test:
Your version is on top. Mine has the same UV layout but I’m getting different results again.
Now I figured that last time my fix was to squash all the UVs within the 0-1 space for the first channel. This worked but it wasn’t really the right way to do it.
As a little test I tried switching my UVs around so they were in the opposite channels. Obviously this wasn’t going to produce the desired result but what it did do was fix the shading errors. Note that the error message at the top is no longer present.
So I’m thinking is there something that might be causing the lightmap to be drawn from the first UV channel instead of the second. It seems that my colour information AND the lightmap is only being drawn from the first channel. Perhaps something is going wrong between exporting between 3ds max and UE4 or maybe there’s just a setting in UE4 that lets the game engine know that there are 2 sets of UVs that need to be read- although I’m pretty sure the latter is not the case.