Some parser functions (and other things) add tracking categories directly, rather than emitting the wikitext [[Category:whatever]] and letting the parser add them. Parsoid currently doesn't include these categories when it parses pages. To fix this, when it calls the API's expandtemplates, it needs to request and use its "categories" output. A simple way to test this is to add {{#invoke:this is invalid}} to a page. If this bug is fixed, the page will end up in Category:Pages_with_script_errors.
Version: unspecified
Severity: normal