See
https://en.wikipedia.org/w/index.php?title=Milton_Keynes&action=history&year=&month=-1&tagfilter=possible+vandalism . Note that the diff size here is wrong, because the software has assumed for the fact that no more results were found that the diff must be for a page creation (thus ignoring the input of the tag filter).
Specifically, HistoryPager::historyLine() assumes that if there is no $next, the revision must be a page creation. That is simply untrue. It would probably be worth switching to instead look at rev_parent_id (which is 0 if and only if the revision is a page creation), in which case the bug collapses into #34922 (which deals with the unexpected consequences on rev_parent_id === null).
Version: 1.19
Severity: normal