There's an obvious flaw in the King of the Kings challenges that can make it unfair for some other managers.

Daily leaderboard ends at 21:00 in my timezone. I happen to have a match scheduled at 20:59 which I can't reschedule since I'm the away team. Not that this matters for me now at the first phase but the last minutes are the most important minutes and that's often where the challenges are won and lost. This has screwed me before at the final phase and surely many others too.

For example why not auto-reschedule the competition games to be a bit earlier or later? My suggestion would be that that at least the last 20 minutes before the end of the daily leaderboard should be free for everyone to challenge without interrupting matches.