“Hi Sol, del.icio.us places restraints on our ability to crawl their site. So if for some reason the item is missed, it becomes very hard for us to retrieve the del.icio.us link. Unfortunately for now the refresh button is your best option when this happens. Sorry for the inconvenience and we hope to get this resolved with del.icio.us soon.”
Looks like this is a restriction on del.icio.us’s end.