No idea why that happens and it goes away if you refresh the page. I have seen it a couple of times and @glemaitre has seen it too once …
Probably a FUN thing and hard to fix, but I have to say it does not look very professional. On the other hand, probably not that important compared to other things!
Thinking about it it seems like I was seeing this because I was logged in “We could not validate your access to this video” so I don’t think this is so important.
Still this could be worth reporting to FUN …
I have not seen it in some time, let’s say it is fixed.
I seen it a couple of days ago 
but we can still say it is fixed
