wOw!! that's some junk filter. My scene was cluttered with unused stuff that DAG Only filtered out.
After some major cleaning up, I didn't find any uv-sets though. Supose to be connected to the shape node.

After playing around a bit (adding and deleting UV sets), I realised that the imported UV set (map1 in my case) simply can't be deleted for some reason. All objects in my imported scene wont allow it. So I copied the UVs to the imported UV set and deleted the other instead. It works, though not as expected.

Thanks for the effort.