single page not caching

single page (example: site.com/contacts) not caching. in settings all enabled. but posts cached normally.

footer from post:

</html>

<!-- Performance optimized by W3 Total Cache. Learn more: http://www.w3-edge.com/wordpress-plugins/

Page Caching using disk (enhanced)
Database Caching 20/21 queries in 0.014 seconds using disk
Object Caching 1708/1713 objects using disk

Served from: *** @ 2011-06-02 10:58:20 -->

footer from page:

</html>