Selling champion that turns into an enemy issue

I wanted to sell a champion , i got the golds but the champion remained on my "deck" and turnt into an enemy one that i could'nt sell When i put it on the board , it didn't count as one of my champion , so i could kinda exceed my limited number of champions I was blocked with that lucian taking place on the side till the end of the game (Couldn't remember if he was attacking my own champions when i put it on the board though) picture of that evil lucian : https://i.ibb.co/v1Z0k2H/thelucian.png