(Not sure if it's a glitch or not)
I joined a game with a custom map (Ranked Server) and pressed the READY button. During the 3 seconds countdown, I clicked on the Daily / Weekly Challenges button and when I came out of that pop-up dialog, the timer was reset to 75 (90?) seconds countdown.
I was the only player on that server. Out of impatience, I clicked on the READY button to un-ready, then clicked it again to reset the countdown back to 3 seconds but failed.
After I clicked on the Challenges button again, the timer went back to 3 seconds countdown and was fixed.