Hi RavenX Mentioned that this graphical error happened with large city squares. This is also happening in haljackey region where it seems he is using large city squares.
I am having the exact same problem at high res( over 1600X1200), With any new region I download , so, I tested rendering my regions at lower res using simcity native command (Ctrl+Alt+Shift+R) and sure enough the problem was gone. Thanks Tungston for the tip
However, I am still having this graphical error when I generate regions using Terraformer
Any clue to what's happening .... your help will be highly appreciated
Thanks