Fullscreen button disappearing

In the practice session before I go out of the box, the fullscreen button is in its place.
http://i.imgur.com/6vjKwXD.jpg

After a couple of laps when I wanna watch fullscreen replay, this button is gone and it's impossible to go fullscreen.
http://i.imgur.com/GnpNjpu.jpg

 

Go to the "Standings" screen, there the Button shows up.

 

I still make this mistake, all the time.....

 

Thanks a lot, brother!