Lightmapping Artifacts in 5.4.2f2

Hi @Kuba. Looks like your are the guy to solve weird lightmapping issues. If you could please take a look at mine, I'll appreciate it.

I'm working on a simple architectural viz scene where I need to place a gameobject very far away from the 0,0,0 coordinates. In my case, (0,2000,0). After baking GI, I get this weird dark spots/artifacts:
After much pain and forum research, and trying everything around, I changed the gameobjects transform position to 0,0,0 and everything worked just fine. Also tried placing the object in Y=500 and it also worked ok but this does not solve my problem:

FYI:
- All the objects are set to Static and meshes have Generate Lightmap UVs enabled.
- My objects do not have custom UVs, just automatic UVs made in 3ds Max. That has not been an issue before.
- Using Unity 5.4.2f2, have not tried with other Unity builds.

This is what I've tried so far with no luck:

• Cranked up to max the Scale in Lightmap in the Lighting/Object panel. This helps with quality but does not remove the artifacts.
  

• Tried baking with different GI Directional Modes. Not an issue.
  

• Changed the Shadow Distance to 2000 in the Quality Settings. Nothing changes.
  

• Checked the FBX for errores and re-imported. Also tried changing the mesh completely.
  
  

Am I doing something wrong? Should I submit a bug report?

Cheers!