When I was a moderator on ELL, I cast a binding close vote on a question with the comment that it was being closed because it wasn't about English. The author had already flagged a similar comment by a user as unfriendly, and I declined that flag. (It was actually the flag on the comment that brought the question to my attention as something that was off-topic.) The author of the question flagged the user's comment a second time, but as "abusive" instead of "unfriendly".
Then the author flagged my "Other" closure comment as abusive and deleted their post, which marked their flags against my comment and the other user’s comment as "Helpful".
Is authors being able to resolve flags on comments on their posts intended behavior? If I hadn't been involved as a moderator, it would have never come to my notice that the author had been able to resolve their own comment flags as "helpful".
After bringing this up on the moderators' SE team site, wizzwizz4 was able to determine that flags on answers could be similarly resolved by self-deleting content, which is a bit more concerning because there are actual penalties associated with rude/abusive flags on answers; "helpful" comment flags just cause moderators to be notified when there are too many raised against a particular user's content.
I'm a bit worried that users will be able to target other users by flagging content, resolving those flags by deleting their post, undeleting their post and flagging the content again repeatedly, although I suspect there may be safeguards in place against that already and someone would need to do some sophisticated sock puppetry to get around them.
I don't think comment flags getting resolved is very serious or that it merits going back and correcting previously resolved flags (at least on ELL, which probably has very few instances of this happening because we've never received a single notification of someone getting too many unfriendly flags). I would like to be reassured that while this can happen in ones and twos, a malicious user isn't able to exploit this mechanic in a way that's difficult for moderators to catch before it's already done damage.