Board Thread:Questions and Answers/@comment-219.97.119.229-20140316051347/@comment-5596770-20140324153845

http://en.wikipedia.org/wiki/Help:Category#Categories_and_templates

"Changes to the template, however, may not be reflected immediately on the category page. When you edit an article to add a category tag directly, the list of category members is updated immediately when the page is saved. When a category link is contained in a template, however, this does not happen immediately: instead, whenever a template is edited, all the pages that transclude it are put into the job queue to be recached during periods of low server load. This means that, in busy periods, it may take hours or even days before individual pages are recached and they start to appear in the category list. Performing a null edit to a page will allow it to jump the queue and be immediately recached."

I haven't seen anything that says they expire. I'm not sure what the bug in the templates would be. I'll attempt to get more information.