Here's something I haven't seen before
(https://www.sc4devotion.com/forums/proxy.php?request=http%3A%2F%2Fimg206.imageshack.us%2Fimg206%2F8749%2Favolonvidmessen6.jpg&hash=0215ad53301661513c4086067355475cfd509e1a)
This was taken from Region Census. In SC4's region view the white band is dark blue. Doesn't seem to affect the tiles, everything is hunky dory once into one of the cities. I saved one city and the band showed up, then it showed up after I saved the other city. Makes me kinda nervous. Wait, got an idea. If it works I'll edit to tell you, if it doesn't, I'll tell you too.
edit: I was poking around in SC4 at the 1600 by 1200 resolution and did some stuff so I saved the city. Went to the other city and completed the rail conection so I saved it too. That's when the band showed up. I changed the resolution back to 1024 by 768, saved the cities and all's back to normal. So I would assume it's best to save the cities in the same resolution that you started them in, at least in my case.
This is a known bug of SC4
1600x1200 region shot will only works if you have around 4Gb of RAM ( BourneID or AleK can confirm that )
Good to know it is a known bug, and that I wont be able to fix it ::)