I fixed a texture problem, came back to this map the next day, a weird purple stripe apears. Also, some buildings dissappeared. Anyone knows how to fix the stripe? Here a video to show how it looks an behave: Video315.mp4
It depends on the map, in particular what color is has as 'Canvas'. You should report that to the author of that mod.
No, it's basically what you see if there is nothing to show. I suggest something that goes close to your 'sky' color, so it's not much visible.