Carnival Horse Season Challenges

I am experiencing a ridiculous amount of frustration and disappointment with the current horse season. My horse is a 105 rank and I am loosing way too many challenges. I understand this game isn't set up for fairness and doing right by it's players and I do take the responsibility of continuing to play. Having that said, I still have to wonder how it is that my horse looses against way lower ranked horses over and over again? I lost 8 challenges in a row with horses ranked 0 - 43. I've also noticed that after training, the game is resetting my challenging horse to a much lower ranked one of my other horses. I have to continue to recheck the box for it to use highest ranking horse. I can only hope that GGS will someday care about perhaps doing things better for us people who do love the game in spite of it's many short comings. I don't mind some challenges, in fact I welcome them but...this obvious disregard to some integrity for the players is really very disappointing and frustrating for sure.