From the results search page, i click on the thumbnail of a document (any type) for preview and sometimes the last page didn't show up. Stay with the spinning gizmo. Did not happend to all document, looks like it happen with mulitple page docs. If i click on the doc name (to see all details), the preview section show all the pages without any problem.
Searched individually, they could be previewed without problem.
But if they are part of a multiple search results, then it seems that randomly , any document could be possibly affect with the preview problem. I know it sounds weird but this is the only constant i observed.