Pantheon Cannot Attack Bug

Was playing a game today and attempted to stun a LeBlanc when she jumped for the kill. She jumped back, my stun did not hit her, and I could not attack nor use abilities for the the duration of that life. I did not get to test if I could attack after death because the game ended. However, I was able to use Smite on players when I was alive.

Sorry, I do not have any gameplay to back this up.