"If the Cat has had some down time then that may be the reason. The default is only to show a day I think so if the Cat was down for 24 hours there might be nothing showing..."

Threads remain active--that is alive and on the screen--for 24 hours. Start a thread on May 1, 2014 @ 10:23 AM and on May 2, 2014 at 10:23 AM it will disappear from view if no one has posted to it. HOWever, if you set the search for three days instead of one at 10:24, there it will be.