Hi likaichung,
No - this delay does not only occur for Auctiva users, but it does not occur for all listings. You can read more information about this issue on the following page of eBay's help index: http://pages.ebay.com/help/find/questions/wheres-my-item.html
If you have any additional questions or concerns regarding your Auctiva account, please feel free to contact our customer support team using the web form on the following page: http://www.auctiva.com/free-auction-software-help/help.aspx
-Mike