[Gameplay] - Twitch does no Damage on Inhibs when Ult is active

Well the title pretty much says it all. I noticed this bug when I was rushing base on Summoners rift with Twitch. I thought that with the Ult i might be able to take down the enemy Inhib faster with my Ult active. Once i activated it, Twitch continued to Auto-Attack the Inhib but did absolutely no Damage. I tried it again today in a Custom game with a friend and it happened to both of us.

I don't think this is intentional. So yeah this is my first bug report and english isn't my native language. I hope this is the way to do this

Thanks Rito and keep up the good work

Kaßs