When I get a notification about updates I click on the icon and muon-updater opens but it says the system is up-to-date when it's really not. The install updates button can still be clicked and updates will be installed but it's really annoying because I can't see what packages are available for update and could be confusing for some users.

Reproducible: Always

Steps to Reproduce:
1. Wait for updates to be available
2. Click on the notification icon to open muon-updater
Actual Results:  
It says the system is already up-to-date

Expected Results:  
It should say there are updates available and list what packages are updatable