Your progress should update once the match ends. You won’t see progress immediately after quitting. Check back after your next match to see if your challenges progressed.
If you are talking about the daily challenge, it will “disappear” but you won’t be awarded the XP until the match officially ends.
You know, it’s complete bull crap that some challenges can remain tracked after getting the quitout prompt (kill based challenges can, but not cumulative score challenges). 343 needs to make it so that ALL challenges can remain tracked after getting that prompt.
Also, the servers are completely awful. I’ve participate in 5 matches and have only managed to complete 1. Again, it’s complete bull crap.
So I had the same thing as you…I got my challenge completion after the game ended so there was a delay BUT I DID NOT get credit towards the event tiers for completing the challenges.