A disputed flag is whenever your flag was dismissed as neither helpful nor declined, or that your flag was reviewed but no conclusive action was taken. This is intended for use in cases where the validity of a flag is ambiguous.
Currently, the following scenarios result in a flag being disputed:
- An active spam or "rude or abusive" flag was cleared (but not declined) by a moderator. These flags are unique in that marking them as helpful can impose lasting penalties on the post and its author, so a special mechanism is provided for borderline flags to be cleared without penalizing the author or the flagger. This can also be done retroactively on already-dismissed flags, if a moderator clears all such flags on the post (both active and dismissed flags).
- A "not an answer" or "very low quality" flag was active on the post while it was being reviewed the Low Quality Posts review queue, and the final result of the review was "Looks OK".
Stack Overflow only:
- A recommend closure flag was active on the question while it was in the Triage review queue, and the result of the review was "Looks OK" or "Needs community edit".
- A spam, "rude or abusive", or "very low quality" flag was active on the post in the Triage review queue, and the result of the review was "Needs community edit".
Disputed flags are considered neither helpful nor declined, regardless of the action taken in response to them. They do not affect a user's daily flag count and don't count toward flag bans.
Note that in most cases, moderators cannot manually mark a flag as disputed (except in the above first case of clearing spam or "rude or abusive" flags), so borderline flags that are manually reviewed by a moderator will generally be marked helpful or declined per the moderator's discretion.
See also: What is the difference between disputed and declined flags?