Weird Boolean Modifier glitch (double faced after intersecting with more than 1 mesh?) I have a boolean modifier with the following settings that is modifying the object outlined in green with the following settings:



where Cube.018 are the 'ribs' around the edges (they are all joined together in 1 mesh for simplicity



I'm trying to cut some holes in the main object (the ribs actually go into it a bit). As you can see, they all work fine up to when the ribs start intersecting with the extruding cylindrical object (that's actually PART of the green object; it was added in edit mode). Then it just starts going haywire with darker double surfaces (inverted normals? I tried flipping normals already though) and whatnot.

Any help is appreciated

EDIT: Not duplicate because nothing 'goes invisible' and as far as i can tell, nothing connects (although that may or may not be the cause of the double surfaced (?) faces. I also removed doubles for both meshes as well

EDIT 2: As requested by Mr Zak, here are some screenshots in edit mode and the blend file:
Interesting. It turned out that if I separated the extruding cylindrical 'sub-mesh' if you will, then everything works out fine. I suppose it has something to do with the fact that I inserted that object in Edit mode instead of Object mode.