Categorization doesn't occur in the job queue when you import an XML dump. RunJobs.php doesn't do anything. Users must launch the refreshLinks.php script after an XML import so that the imported pages appear in the categories.
Furthermore... the fact that the categorization is asynchronous is a real problem. This change in the categorization process is a bad thing, especially when your wiki uses semantic extensions. This could have been a config choice, it should not have been imposed.
Thanks in advance for your action.