Calling https://commons.wikimedia.org/w/api.php?format=xml&maxlag=5&action=query&list=categorymembers&cmprop=title&cmlimit=max&cmtitle=Category%3ADiagram+images+that+should+use+vector+graphics&cmnamespace=14&rawcontinue while logged out returns a `categorymembers cmcontinue`, though there are less than max categories.
Example result (archived): https://phabricator.wikimedia.org/P686
Using the offered continue key, just an empty restult is returned.
https://commons.wikimedia.org/w/api.php?format=xml&maxlag=5&action=query&list=categorymembers&cmprop=title&cmlimit=max&cmtitle=Category%3ADiagram+images+that+should+use+vector+graphics&cmnamespace=14&cmcontinue=file%7C4255475a494c4c41204c4946454359434c4520434f4c4f522d415155412e504e470a4255475a494c4c41204c4946454359434c4520434f4c4f522d415155412e504e47%7C2809558&rawcontinue