If I remember well, I ran into that bug a while ago as well. I had sort of grey colors for the section cuts in LayOut for some sections and there was no way to change them to black in LayOut whatever I did in SketchUp. I ended up exporting and inserting those sections again from scratch.
Maybe post this question and the file on the official SketchUp forum?
Edit: original post on this forum with same bug? http://sketchucation.com/forums/viewtopic.php?f=15%26amp;t=62746




