Hi Felix, that kind of bleed through of edges in thin areas is a display artifact - it's a side effect of the process that makes edges not get drawn submerged and partially obscured within their surfaces. There currently isn't any way to control it, it's just a display glitch to ignore.

Some more detailed info in this post here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4061.6

- Michael