When switching resolutions, or in my case changing from full screen to window'd, the next loading screen will appear upside down. A good way to reproduce this is to open D2X-XL and go from full to window'd during the intro cutscene. The loading screen immediately after will be upside down.
To note this is purely cosmetic. Once the loading is complete everything returns to normal. I haven't found a way to make it actually detrimental so this could be considered very low level. It's just a bit jarring.