YouTube play progress bar not hiding

I was wondering if anyone else is experiencing this issue?

Up until yesterday (I haven't installed anything or done any software updates for MacOS or Safari) when I was watching YouTube videos, after I had clicked the box at the bottom right of the screen adjacent to the play progress bar, after a couple of seconds or so, the play progress bar and the other on-screen graphics would automatically hide.

Now, no matter what I do, they will not automatically hide. I've Googled about the issue, but the things mentioned, such as moving mouse/trackpad arrow to the bottom left, right, or the very bottom of the screen, do not make any difference.

I was wondering if anyone else has/is experiencing this issue and also if you have managed to find a fix for it?

Thanks in advance.