YouTube full screen glitch. Please help.

When using safari (on my iPad mini gen 5), when I play a YouTube video from the browser and go full screen I sometimes get this glitch where the video only takes up a quarter of the screen. The quickest resolution is to turn my iPad right side up and then back in the position I was using it (I keep it on its side due to my keyboard case). Sometimes the issues will randomly resolve itself but I’d rather not have to constantly take my secret from the keyboard dock to get the video to play in full screen as it should.

Please help.

P.S. For what it is worth, I do have my text slightly larger on my iPad mini. I could just use the app but I prefer the way it works on the browser.