It Seems to me like a morality and form issue of your players (However I am sure you know this).. Had the same several times, very annoying.. After that kind of matches usually I am not able to win anymore
I usually never listen to my coaches and their advices. You are the boss so you should know what to train to your individuals. I never reduce the heavy workload for youngsters when they complaining about it. However it could end up with injuries but I take that risk for their future development...