Taskbar appearing during video fullscreen

A short while ago a problem began happening where the taskbar appears while I am using the video player in fullscreen. When I initially enter fullscreen mode, the taskbar is always hidden like it should be. However, after a period of time (which varies from 5 seconds to over 20 seconds) the taskbar will pop up at the bottom of the screen. Fullscreen mode does not exit when this happens, the video will continue to play as normal. However, the taskbar is overlaid on top of the video control bar as well, which makes it impossible to pause/fast forward/etc. without exiting the video and then reentering it.

I did not alter iTunes in any way before this problem began happening. I uninstalled and reinstalled iTunes but the problem persists.