Enemies not caring if they're taunted?

I love playing Shen a lot, and more and more recently, it seems like the enemies I fight just do not care that they're taunted. Either walking in a direction that is not towards me, or just continuing to attack whatever they're already attacking. A lag issue? I don't know, but in a world where I want you to punch me in the face, and where taunt only lasts 1.5 seconds at the best of times, if they enemy ignores the first second of taunt from maybe lag, or who knows why, then taunt was basically meaningless.

I'm not saying it happens every time I use taunt, but many times now, I've taunted an enemy and they just keep on doing whatever they want to do. It's not right! In this last game, I taunted Nasus as he was tower diving, and he put an auto attack onto the tower, then he put an empowered auto attack onto the tower. Then the taunt ended, and he put a third auto attack onto the tower, taking it down. That's not what's supposed to happen!!