Hi Madmenyo,
This proper fix is to use the methods that has mentioned above.
Adjusting the Indirect Lighting Smoothness and Quality will help in this regard.
The alternatives are to import as a single object or use other pieces of geometry to cover the edge seams.
You can also take a look at this thread here: Modular Asset Lighting Problem - Rendering - Epic Developer Community Forums
In the next week or two this will be covered on the Wiki guide that Eric and I have setup here: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums
I’m in the process of getting this setup and finalized in a more formal manner than the forum thread above.