Hi, this has been an issue for years now. Navigator is sometimes not updating either changes to an image I'm working on or even the actual picture. This happens in library module as well as in development module. As this occurs only sometimes I cannot find any rule to this thing. Thanks for some advice.
If you select one image and go to Develop and then open the Presets panel you should be able to hover your mouse over any named preset and see the navigator change as you move up and down the list. Is this not working?
Please try and reset the Lightroom Preferences and see if that helps.
To reset your preferences, do the following:
Navigate to the preferences
file: Mac OS: /Users/[user name]/Library/Preferences/com.adobe.Lightroom5.plist.
Windows 7, 8: C:\Users\[user name]\AppData\Roaming\Adobe\Lightroom\Preferences\Lightroom 5 Preferences.agprefs
Rename the file to Lightroom 5 Preferences.agprefs.old
Let us know if that helps.