Thresh R Bug?

What's up summoners??

Soo, i was playing thresh the other day and i THINK i stumbled on to a bug, might just have been me missclicking.

We had pushed into their inhib turrets so i walked up towards the base walls blind casted a hook through the wall for pressure, not going in just laned a hook to stop someone from walking up to defend turret. As my hook lands (on ) my ult got activated. I loked down at my key board and my finger wasnt even close to R-button. I'm quite confident i didnt press the button so i wonder if anyone else has seen this happen?