Safari Window disappearing when minimising full screen video?

So basically when my Safari window is in full screen mode and I am watching a full screen video on Netflix or Youtube, if I try to minimise that video my whole Safari window disappears and will not reopen when I press the Safari button. I can also still hear the video playing and this will only stop if I quit Safari. The window is not minimised as there is no window in bottom right corner. Also this doesn't seem to happen if Safari is not in full screen mode before I maximise a video?

I hope that makes sense and I'm probably being stupid but this only started a few days ago and I don't have a clue what is going on but it's driving me crazy!