I've just spotted this message too.

My mistake, just tested again and my helpful post flag count didn't increase: before, after.

FWIW this also appears to happen from manually deleted posts and those deleted through the LQP review.

@TheLethalCarrot I don't like that! NAA flags that end up with the post being deleted (by vote/consensus) in the LQP queue should definitely be marked as helpful. I can (sort of) see the point for those deleted by the OP after the flag was raised ... but not entirely.

@AdrianMole None of those in my screenshots were deleted by the OP, all by >20k users.

@TheLethalCarrot Seems that there is some confusion in the moderator team(s) about what is happening, too.

From MSO, it's a bug

Yes, and according to @YaakovEllis 's answer, it's been fixed.

@Daniil "This has been fixed. Moving forward, any post that is deleted with active mod-attention flags (ie: not close/delete flags) will have the flags deactivated on post delete". Is there something I'm missing here?

@Ollie from the linked comment: "It looks like this change is affecting more flag types than it should. We'll be fixing shortly."

@TheLethalCarrot oh. Thanks.

Several years ago, this flag type used to be called "eventinvalidated".

@SonictheMaskedWerehog and that’s exactly what I as a moderator see on that post.

@MartijnPieters And, let me guess, "aged away" shows up as "scheduledtaskinvalidated"?