Comment 5 for bug 1617217

One theory is that the plugin manager is not doing the right thing here, because if you, after step 3 exit the About panel, then enter it, then perform step 4—you get a warning from the plugin manager that “system-update” can't be found. The other theory is that the system-update plugin isn't cleaning up properly, which is unlikely because the bug cannot be triggered without going via the About panel.

Will confirm one or the other by changing the plugin instantiated by About with something closer to pure-qml, e.g. Hotspot—or create a brand new, empty one.