Pink areas on terrain when height added

So when I add some height to my terrain I see these pink areas, they don’t disappear even when I build the game. Is this a bug or do I not know something? I hope I don’t know something. My unity version is 5.5.0p3 and I bake lightmaps by the way if that has anything to do with this. But this happens in an even weirder way when I use realtime lighting.

okay this is apparently because “compressed” was checked with my Baked GI