and then I look up a little..

This used to happen to me when I would clip a brush wrongly or atleast think I did. Netherless I remade the brush and reclipped and that fix that problem. This also used to happen to me when I would set the radias of light too high causing the same graphic glitches. Don't know if this helps just thought I should share 

seems to happen when I look directly at the rest of the map (whole map is in my view, even if there's a wall in-between). Im going to try to reduce my brush count but if that doesnt work I may have to restructure my map

I see that kind of thing sometimes from a decal , mainly if i move or resize a wall it puts the decal out of place.

its because there were too many surfaces in view, went on a caulking spree and its all good now