Try exporting to glTF format and import into Blender 2.80 with built-in importer, may be you'll have better luck there.
Thanks, that worked for me. It's a pain to switch back and forth between 2.8 and 2.79 but if that's what it takes.
Sadly, I can't drop 2.79 just yet as it has plugins that help with turning meshes into 3D printable objects.
Looks like they are using UDIMS or a very custom UV laying setup then what most studios would use, each part of the materials on the meshes have different UV scaling set to them all in the one UV space (or multiple if using UDIMS), there is now a experimental udim blender one could try to use, if not you need to separate each part manually to easy align the UVs to the textures (once you find each for each part).
I started that, but some of the ships are just too complex. It would take months. I took a screen shot of the UV layout preview in UE Viewer and layered it on top of the texture as a guide.
The strange thing is, on one or two of the meshes, the UV Layout was exported just fine. I haven't looked at them all yet.
It might be as you said, as those were simpler meshes, and for the complicated ones, they set material ID's for separate groups and had a layout for each of them individually.
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