James Van Ells wrote:
First thing to do is check to find the source of the problem. Put the camera on a verified level surface, tripod, table, car boot, whatever. Check the level in live view to see if the camera is in fact the problem. I have had my computer folks tell me most of my computer issues are related to the very common PBCK type of errors. Problem Between Chair and Keyboard. Really if there is a camera issue, contact Canon and see if there is a simple way to calibrate the level.
Newbie mistake, not reading through the thread before responding.
The OP, had already run the diagnostics! It's not just a little off, it's considerably off. See the picture that was posted of how much the camera needed to be wedged to get the shot to level!
The camera is being sent back to Canon for service even though it's out of warranty, because the problem is likely a manufacturing error!