Graphical Bug In Game Tab

Screenshots:

This happens in the game tab and in the build. I have a ‘AMD Radeon R9 280x’ if that helps. Does anyone know why this is happening?

EDIT: This happens in 5.3.5 and 5.5.0. Also I’ve updated my graphics card to the latest software, and reinstalled unity several times.

I guess this is the same issue.