We have Flagged Revs in huwiki. This edit was made by an anon, and an admin hid the inappropriate summary. https://hu.wikipedia.org/w/index.php?title=S%C3%BClys%C3%A1p&curid=45101... After this we couldn't review the version. The message was: Unable to review this revision. The target revision does not exist. (Source fo English text: https://en.wikipedia.org/wiki/MediaWiki:Revreview-failed and https://en.wikipedia.org/wiki/MediaWiki:Review_bad_oldid)
In fact the revision did exist, only the edit summary was hidden. Is this a bug or a feature? :-) I am not very familiar with Phabricator, so is there a ticket for this feature already?