Banshee's Veil consumed on my spells to protect the enemy

I had a game as a pantheon support and i was laning against bard and kalista, any time i would try to stun the bard with my W once i had purchased a Banshee's Veil it would consume my Banshees Veil and not stun him or damage him. It would also prevent me from using any of my spells until i stunned something else when my cooldown came up. I don't know if this is a constant occurrence or if it was just the one game, but should this be happening often this is a huge bug that needs to be dealt with, thank you for your time.