Mu Yanling, Sky Dancer’s +2 ability states that target creature gets -4/0 and loses flying until the beginning of your next turn.
In actuality, any creature with flying will regain their flying at the beginning of the opponent’s next turn, while the -4 portion correctly remains until beginning of my next turn.
Tested against Jodah, Isperia and Szadek - they all regained flying as soon as my turn was over and flew right over the defender I had prepared for them 