Black meshes after Lighting Build

Hello, I’ve got major issue here. I will be as accurate as i can.

So I’ve got big asset pack of low poly meshes.(low poly universe pack) Those meshes turns black after building lighting. It only happens with this specific asset pack. It was made for UE 4.12 or something. This is the way i did it. I opened this asset project using UE 4.12 and 4.20 ( 2 tries) and then i used migrate option to copy it to my project. Meshes appears to be fine until i build lighting. all goes black. ( Other meshes from other asset packs works fine). Those meshes which now turns black used to work for me with my previous journey with UE4 (half year ago). Now they are not.

I did try to change Light map resolution. I did try to change light map index. This fixes the issue until i build lighting again.

Those meshes are uasset files.

So please… help. This asset pack is very important to me beacuse there are hundreds of valuable meshes to me.