I guess randomising them is what goes on because in a case where the 'challenged' might have knowledge prior to him accepting the challenge of how the questions are and exactly how to answer, it won't be much of a challenge then, if you get what I mean.
And maybe just maybe, to eliminate bots idk
Allan Is Awesome I am talking more about how the challenge invites are sorted or quasi sorted in the challenges tab of the Android App. Notice how one of them is out of chronological order in the link I posted? As to when they are done, the receiver can choose to do them in any order as long as they are not expired.
Now I get it. It's more likely the time the challenge sender completed the challenge for it to be handed over to you is what I think makes that difference
Come to also think of it, that C++ challenge expiring in 8 hours may have most likely had the other guy not had completed all the questions due to issues like network or something and went offline, thus abandoning the challenge. From his side it will be reading 'YOUR TURN' then when he clicks on it it will have him 'Continue'
If you noticed his answers, there may have been somewhere he might have not answered the questions at all. That's what I think went on