When I played Count Caldwell to draw 2 new Lyrian Arbalest + cards from deck, the first one killed an enemy that was locking one of my light infantry. When the light infantry was unlocked it went back to its original row filling the row full. I could then use its order to move it to the other row and did so.
Doing this however caused my second Lyrian Arbalest + to bug and just stay floating above the deck, unable to be played. The card remained this way until the battle was finished.