Artifacts at seams when baking lightmaps!

When I bake light in my scene with one of my models, Unity creates artifacts at the seams.

What I have tried: Increasing "Baked resolution'' from 80 to 160 - nothing changed. Increasing "Baked padding'' - nothing changed.

Create my own lightmaps in the second unwrap channel in 3ds max - nothing changed.

I tweaked multiple settings in unity but nothing fixes my problems. Here are my results:

http://puu.sh/s59Xz/a66aec987d.png Here i created the lightmap in 3ds max with flatten mapping, now there are artifacts on all seams.

http://puu.sh/s5a0Y/3d4731a2b3.png Here I enabled the "generate lightmap UV's" in Unity, less artifacts, but they are still there!

http://puu.sh/s5a49/70b0607f6c.png Here I unwrapped the upper part of the mesh in 3ds max by hand (without flatten mapping). Note that there are artifacts on the ceiling where there are no seams (it's an Ngon). Unity still renders artifacts at the seams: http://puu.sh/s5a9R/f0ff990c7b.png

This is very weird for me as i have baked lightmaps in unity before without any problems, even my colleagues have never experienced this before!

If anybody knows a way to fix this it would be much appreciated. I've looked all over google and unity answers, but haven't found anything that fixes this.