[nightwave Mow Them down keeps resetting the kill count]

I have this issue as well, and I've done some extra work investigating it.

 

I've had the kill count reset after*:

- manually reloading

-performing a slide

- a companion or myself dying

- extracting

 

If you manage to avoid those resets, you'll get 2,000 Nightwave rep from completing both instances of Mow Them Down, however they'll still stay active in the Nightwave quest log, and are repeatable for another 2,000 rep. At the [edited] time of writing, I've earned 5,000 rep that I shouldn't have [1k from the Mow Them Down from two days ago becoming active {and completable} again, 2k from seeing if they could be completed again {which, as I said, they can}, and the remaining amount just from normal play, without actively trying to complete Mow Them Down]

 

* This list is anecdotal, based on my own observances, and is not guaranteed to be complete or accurate.

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