the item cannot be downloaded

I subscribe to iTunes Match. When I look at all my music (not just downloaded) in iTunes on my Mac I see songs with the available for download icon (cloud with a down arrow). They either say "Matched", "Purchased", or nothing at all in the iCloud status column. If it says Matched or Purchased then I can download the song or stream it. If it says nothing then when I click the download icon, or try to play it, I get a message saying "The item cannot be downloaded. The item you have requested is not available for download". If it's not available how does it know it's there and why does it show the "available for download" icon? Is there some way I can force a refresh of the music catalog?