Trouble with Resource Reservation => Resources not appearing

Just curious if anyone else has had this problem, and if so, how did you fix the problem? We have created a list of resources on a site. When we go to “New reservation” and click on “Find a resource at a specific time” and search…not all of the resources are listed even though I know that none of the resources are reserved for this time. If I click on “Find a time for a specific resource”, all resources are shown. Any help?