Rocket Grab pull in fail! Arcane shift cancels it out!

ok I was playing a game earlier today as a Blitz crank support, I was fighting with my adc Teemo and we were against a ezreal and a soraka, anyway as my bud was invisible I was lureing in ezreal to come in closer so i can pull him in and uppercut him so that way teemo can still attack him why he's in the air!

Now when i used my grab ability on him, it hit him, but as it was pulling him back all of a sudden Ezreal suddenly used his arcane shift while he was being pulled in by my grab, the arm was still attached to him as it happened right after he reappeared and I thought, heh your still getting pulled to me, but then to my surprise, Ez was running the other way with my arm for 1 second and then the next the entire arm animation just disappeared!

Both me and the teemo said WTF? in chat confused on why he wasn't pulled in! At first we thought it wouldn't happen again

guess what IT DID, the grab was successful again and just when he was about to reach us he used that skill and tped away from us and the arm with him until it disappeared!

This Glitch or bug usually happened when the blitz grab is at it's farthest/half farthest way, and just when the grab is good and starts pulling ez uses that ability again and cancels out my grab by him not coming to me after he reappeared with the arm still clearly attached to him!

It was complete bs that game! I really wish I was recording but my frame rate gets really bad all of a sudden during that..so yeah...anyway

Aren't Blitz's rocket grabs silents people while they are being pulled in/can't be used during the grab? Cause Ez sure as heck was able to when he kept escaping with the teleport even the arm made contact with him and started pulling him in!

if this is a bug/glitch then please patch it!