[GAMEPLAY] Blitzcrank auto-ing tower after successful pull

During some of my recent Blitz games, I have noticed that Blitz will auto a tower instead of a champion after a successful grab. I will be underneath the opposing turret, and will hook an enemy champion who overstays. Once the hook is landed, I queue my knock-up for when they arrive, but instead of knocking up the champion I just grabbed, my champion uses that empowered auto on the turret (I leave auto-attack on with Blitz, so that ideally I wouldn't have to right click the champion myself).

I feel this is a bug or some other unintended effect with Blitz, and am hoping that it gets looked at. It has cost some kills under tower. If this is not a bug, hope someone lets me know, because I have never had this happen before, but it has now happened multiple times. Based on the wiki, "Blitzcrank will attempt to attack enemy champions that are successfully pulled towards him" is written in the Q - Rocket Grab description. Hope to have this looked at, or at least someone tell me if I am wrong here. Thanks!