Howdy! I have noticed a few times now that the game sometimes freaks out when you try to use a lunge attack (move then attack) with no valid target available after the attack. This forces me to resign the round. Sad. Your game is otherwise perfect, by the way.
Freak out? Perhaps you're missing the done button on the bottom right of the screen. It is in an out of the way place and if you're missing it, it's an issue.
Is it a bug that you have to hit one of your own guys when no other target is available? The "Done" button doesn't appear when one of your guys is the only available target. Come to think of it, should you be able to cancel the attack part and just use the move even when you could hit an enemy?
It's not a bug. There are many other threads about this issue, as well as many discussions about canceling cards.