Some users had problems getting that badge. The solution was to leave the challenge and join again. That is the standard solution when that issue occurs. It happens from time to time.
Since challenge badges can't be awarded after the challenge has ended it is important that you check right away if you got the badge or not.
That's disappointing as I just thought it would be given at the end of the weekend and had plenty of time to cancel and rejoin. Lesson learned! Thanks for your response.
