Importing a mesh with several UV maps

I am currently trying to get to successfully import a mesh with 5 UV maps to UE4, from 3DSmax ; no matter the parameters, no matter if I ask UE4 to generate lightmap UVs or not, the three UV maps I see in the asset editor are:

  1. (photo) a map with giant red lines (it’s too big for me to understand what it is)
  2. (photo) the five UV maps fused together (thus heavily overlapping) ; however, the mesh has the five materials that I applied on 3DS before exporting, and they match their correct parts (photo). Applying a material on them immediatly makes them, except for the ropes, invisible.
  3. (photo) what appears to be UVs of the two ropes that I have on my scene, but not unwrapped. I know that these are really the ropes, as when I apply a material to this slot, it’s applied to the ropes. But I also can see their correct UVs in the second map, somehow?

The mesh works fine in Substance Painter, so I’m pretty sure that the problem is in UE4, but I can’t find what’s wrong.