I think that the bug might have to relate with multiple screens loading in the game. I once experienced a similar situation where I started a match, and on the screen where you meet your opponent, a blurred out version of the cloning chambers appear, notifying me that the cloning is completed. The cloning chamber notification disappears when I click it and the match continues on as normal. My guess is that in your case, instead of the cloning chamber, its the rivals race results screen. The game then runs a match and then you can't access your rewards and the match can't be controlled properly. Its like playing the game while your blind or that a malware placed a screen wide advertisement that always stays on top.
