This CL season I've had at least three instances where I would have a chat with my opponent and then accidentally end up having chosen to defend.
I used to think that's because I hit Enter and it would choose the result I had been hovering over, but I wasn't able to replicate that in a friendly against @Ducke.
When Ducke tried it, things became even stranger. On his side his timer had run out and he was given the result he wasn't hovering over. On my side it looked like he had 7 second left and chose to defend.
Something's amiss here.