An interesting phenomena is occurring as I'm testing https://github.com/FreeCAD/FreeCAD/pull/2605
When I open the addon manager and scroll to an addon that has a pending update, the first time I choose it I will see:
An update is available for this addon
Now if i scroll away and click on another addon and then come back to this one again
The message has now shifted to:
This addon is already installed
without actually reminding me that there is a pending addon if I want it.