If you count the sectors, the grid is being displayed incorrectly. You'll note that there's a single row 1x5 grid at the upper left, then a 5x5 open area, then some more grid. My guess is that somebody blew the indexing on the upper left to lower right grid coordinates, and started indexing with 1 when they should have started with 0, or vice versa. It may be that the AMD Radeon HD 6800 series GPUs handles coordinates in a peculiar way.
The nice part about this bug is that it's stable, so hopefully finding and fixing it will be a straightforward task. I'm also getting the occasional building that's offset by one row on the same axis, until I reload the display, and that's likely to be part of the same bug.
