Possible 'Beat the grineer' bounty bug

[(PSN)CuddlesForDays]

A bit hesitant to post this in case I was interpreting what happened wrongly, but I was doing the bounty where you had to get more kills than the grineer squad. Usually this is no problem, especially as I normally play solo, but accompanied a friend this time on a lowest tier one as he  hadn't done a Deimos bounty and wanted to get to grips with things. Anyway, we got to the objective and a friendly necromech we had found was also there. We got pummeled scorewise, and I was wondering if kills by the Necromech were counting towards the grineer's total? Was a bit weird going from getting the bonus every time to losing. I know my teammate wasn't the best, but it shouldn't have made quite as drastic a difference as that.