Ennemy champion in my bench

So I was playing a ranked game with brawler units when suddendly, one of my Rek Sai turned with red hp. It woulds just stay in my bench, not combing to make a lvl 2, not beeing able to sell it after many tries and not beeing able to play it on my field! Same thing happened with a Kindred later on but i was able to play that kindred. Obviously I lost the game because I was not able to do anything.

Did it happen to someone too?