Invisible Champion

I can't remember the exact situation but I'll do my best. With two 1* Garens in play I selected a third from the carosel. I was teleported back to my screen expecting them to combine. Before they got the chance I picked up one of the Garens causing the other to become invisible. The one I was holding then became untargetable however I could still swap it if I selected a different unit first. I sold it and moved on. However, at some point I realized that I still had both the Noble buff and the Knight buff even after all Garens had been removed from the board.