Hello. What I think is happening is that the game has a few different, random "appearances" for the upgraded SdKfz 251.
As far as your lighting question, I believe your problem is your burn settings if you are saving _nrm, _gls, and _spc separately.
Huh. Interesting catch on the randomness. Odd that it's happened every time for me, but I'll try some more tests on my end.
As for the lighting, I only tried including the nrm/spc/gls files because I was experiencing the same issue as this:
https://www.coh2.org/topic/37265/skin-mod-gloss-question/page/1#post_id554377
I meant to include screenshots, but didn't get around to it, sorry.
Several vehicles are probably too light, but the Sdkfz 250 is the most noticeable. What should be pure black is nothing like it. It just seems to be a mistake with the default files the mod maker uses (my best guess is that it's using the much lighter snow-based textures on some vehicles instead of summer textures).
So for that reason I tried using textures from the PSD files, but that sends the lighting on pretty much all the vehicles completely crazy. It's most noticeable on low-angle lighting maps like Crossing in the Woods when you turn the vehicle around. After some research last night, it's possible I need to disable 'flip' for the nrm/gls/spc burn settings.
If you have successfully burned nrm/gls/spc files, I'd definitely love to see your settings.