Selling a unit last second transformed it into an opposing unit that was stuck on my bench.

Sorry for the Plays.TV video but it's the only thing I have. I sold a a millisecond before the round was over to get the economy bonus gold, I recieved that gold and the bonus , but kat was stuck on my bench, this time with a red health bar and not able to be sold. I could put her on the board, but had to attack her in the next round if I did so, It also changed from counting as a unit of mine to not counting as one between rounds. When she was on my board, I couldn't rearrange my other units at all, so I kept her on the bench which resulted in me having one less bench space throughout the whole game. I don't know if this can be recreated and I do not intend to try until there is a practice tool ;)