What's up with the lock on auto attack?

I had watched a video on Lee Sin, and it had explained how to do the Flash Kick, and said to practice it on the dummies in practice mode. Well, I ran into a problem. When I had multiple target dummies out and tried to do multiple flash kicks for muscle memory purposes I found my champion kept trying to run back to the first dummy I ever targeted. This is seriously annoying. Is there not a way to turn that off? Even after I hit the third dummy Lee Sin would still run back to the first