part edges not showing in drawing?

I've got this drawing, and I'm trying to make a flat pattern for our shop to work with. In the other 3 view and isometric, all edges show. However, in the flat pattern, it will show everything *except* the part edges. I've tried rebuilding, saving closing and reopening, I've updated graphics drivers, I've placed the view in each way and repeated the other steps with those other attempts, etc. Any known cause of this?

From left to right, we see how it looks normally, how it looks in edges+colors shown, and the far right shows that the edges exist, just aren't rendering or showing for no apparent reason. No edges are hidden, tangent edges are visible, no errors in part.