When Blitzcrank pulls, must wait a full 5 seconds or Dunkmaster Darius pull doesn't work [GAMEPLAY]

I was playing ARAM, and my team had both Darius and Blitzcrank on it. Blitz would pull an enemy, and then I, as Darius (Dunkmaster skin), would activate my E to try to pull them further a bit more and interrupt their attempts to escape. The enemy would not get pulled, but I would still get an assist when the enemy champion died. This happened at least 6 times. It only would visibly pull them if I waited at least 5 seconds before attempting to use my E on them. I also experienced auto attack targetting malfunctions. If I had just used my ult, the ult target reticle would not disappear unless I manually left clicked out of it. If I didn't do that and kept right clicking to auto Darius would just stand there doing nothing. Also, when I would ult someone and kill them, no timer would begin and I could continue to ult even after 20 seconds. Lots of bugs on him in this game. Didn't you guys disable him just earlier this week?

1. ARAM - Howling Abyss
2. Have Dunkmaster Darius, Regular Blitzcrank on the team. I don't know if the other champions matter.
3. Have Blitz pull an enemy champion.
4. Darius immediately follow up with his own pull.
5. Proceed to kill the champion, no visible pull from Darius would occur but you still get an assist.
6. Kill an enemy champion with Darius ult.
7. Attempt to right-click and auto attack another nearby enemy champion.

The issue occurred practically every time I would follow Blitz' pull up immediately with Darius' pull.