Zonewarden Challenge: Hammer/Anvil, is anyone else having trouble?

For those who don’t know, the challenge is as follows: “in a single run, defeat one runner with a melee attack and another with a grenade.” I did just that last night and it did not complete for me.

I was on perimeter, got into a fight and downed the last guy on their team. I saw he had a self-res so I figured it’d be a great time to take advantage of his vulnerability. I waited for him to use the self res, he got up, then a threw a flechette grenade (only grenade i had on me) at him, which killed him.

Later on in the match I came across a rook, whipped out my knife, downed him with the knife. I figured this would have fit the criteria of the challenge. However, when we extracted and I checked the codex, the challenge was incomplete. Does anyone have any idea why?

Now, I did do a finisher on both runners after they were downed by the grenade and knife. Could that have affected it? If so, that’s frustrating. Is it because the challenge said melee attack and another with a grenade and it has to be in that order? Does the flechette grenade not code as a grenade for some reason? I’m very confused and a bit bummed out and frustrated by it. If anyone has run into a similar issue or has any insight, or even has completed the challenge, your feedback would be greatly appreciated. Thank you.

Extra tidbit: later on in the night I completed the challenge “clusterluck” which is to defeat two runners in a single run with frag grenades. I did this by throwing a grenade at two already downed enemies which full killed them at the same time. Perhaps I’m misunderstanding what they mean by “defeat”? Not sure. Thank you for any feedback.