The list of potential "culprits" is pretty large. These scanners have lots of different settiings and any other (or more) of them can prevent a Favorites List from being scanned.
While you are not seeing the "Nothing to Scan" message, the same things that would cause this to happen are possibilities for your situation. (I'd bet if you turned off the Quick Key for that Favorites List the scanner is scanning, you'd probably see "Nothing to Scan").
http://forums.radioreference.com/un...4-x36-nothing-scan-checklist.html#post2121181
You might also look at page 79 of the most recent version of the manual. There is a section on Troubleshooting Scan Mode, Nothing to Scan.
Lastly in Sentinel, be sure the Quick Key for the Favorites List is enabled (Profile Editor section) and Quick Keys for the System and Department/Sites are enabled. While these are enabled by default, you may have inadvertently disabled them when doing some programming.