[GAMEPLAY]-Blitzcrank's Q hit wrong target or go through target

I was playing support,Blitzcrank .Me and Vayne vs Soraka and Teemo . I really like to grab from walls and bushes,but this happend. Teemo was staing still (trying to use passive i think) and behind him-Soraka I used my Q on Teemo ,but arm IGNORED Teemo and pull Soraka directly behind!!! I was like- WTF! OMG WHY ME! This happend to me 3-4 times in game! PLEASE fix this! :/