This has happened enough that I feel it should be reported but, since it seems random, probably not fixable. Often, in a fight, a character or summons will either be unable to be moved, cannot attack, or can continuously attack without result and without APs left. This can be fixed by saving, closing the game, then opening the game. In the case of the continual attack capability, simply "end turn" - I have yet to see it repeat the next time the character can use APs.
I believe there are more post update bugs - I'll add them here as I remember them.