Selling my aatrox made him go back on my benchas an enemy.

I sold my Aatrox and his hp turned red. I got items from him but couldn't put any on him again. I was able to move him into fight, every round he turned back and started attacking my units, enemy team also could attack him. I couldn't upgrade him or sell him again. In the last round I sold my all units and put into the play only him. The round immediately ended without a fight. I recorded it with fraps may upload it later.