It doesn't work when you want to pause video after clicking timestamp. For example you can find links to specific time in description of this video https://www.youtube.com/watch?v=eg13JWKEt0M When you click 1:17 and then try to pause space works as page down
It has been designed in such a way that when you click any active element on the page, it will perform as space bar, only in no focus cases it will work as pause/play
