Using the default UI map box when fully zoomed out some of the larger zones will have parts disappear. I was wondering if using a smaller UI box would solve this problem and have the maps fully displayed.
Any other solutions to this issue are greatly appreciated.

hummm, I didnt know you could change the size of the map box.. what is the command??

mousewheel

There is a button on the UI map screen that you can push, turns it off like if you unchecked a box, for the life of me I can't remember what it's labeled. Play around with it and see if that solves your problem. I think it's the square button below the "Labels" button.

turn off height filter

turn off height filter
or set them both to 1000.

The height filter isn't the problem here. It seems like there's a limit to how many lines can be drawn on the map at once, possibly to keep overly complex maps from slowing down the framerate. As you zoom out it has to take more and more lines into account, so eventually some start getting dropped.