From time to time, some accidental failure causes that any page (after its edit) is not displayed correspondetnly to the updated category tags but remains displayed even in the category whose tag was just removed. However some such fails remain active for monts or even for years, unntil the page is edited again.

An example: this image was moved 2018-03-28T19:06:44 from the Category:Zvolen to the Category:Pustý hrad. However, stil in 2018-07-14 it was not visible in the category Pustý hrad and was visible in the category Zvolen. Just a new edit of the file pages caused a normalization.

There are 2 tasks to be solved:

• to avoid the display/indexing failures
• to do periodical and automatical update (pretended edit) of all unedited pages to fix such failures (and update categorization if conditioned by variables etc., T86492).