Itunes won't stay full screen on my PC. It keeps shrinking / readjusting no matter how many times I maximize

I have an issue whenever I'm playing a video in iTunes where if I maximize the video on my second monitor so I can do things on my primary monitor, the video will just randomly shrink from full screen to the height of the video and it can take up to 13 attempts to get the screen back to maximized (it just keeps shrinking within seconds).

There is a second-related issue. I can maximize the window by clicking the square at the top right of the window next to the X that closes it. If I use the specific Itunes button at the bottom to go full screen, then I lose audio.