Whenever I hover over a language link with the language submenu open, an unexpected yellow background-color appears. This issue seems to be caused by the CSS rotation used for animating the menu opening.
The problem is only noticeable on non-retina screens.
Take a look at this image to see the issue:
Check out this link to see the problem in action:
I discovered that commenting out the CSS rotation used for the unfold animation fixes the issue. However, removing the rotation is not ideal because I specifically want that animation effect.