I just got a point towards this Challenge in Co-Op Mode a few minutes ago. While I have not had a chance to test it further, it appears the way to get credit for this milestone might be to actually defeat the enemy with the damage from the Pull ability, not just Pull them towards you.
Unfortunately, after further testing this evening, although I was able to defeat multiple enemies with Pull, I did not receive any further credit towards the Challenge. Back to the drawing board, I guess...
Same here, killing them with the pull seems to do it some of the time, but it’s extremely inconsistent. Some kills will count and not others. Honestly the milestone is just extremely buggy and needs to be fixed.
