I started out with one instance at a LTS version, the other instance at a more recent version. Don't remember the exact versions. I've been keeping up to date as new versions are available for each instance. A while back both instances were updated to the same version.
Anyway, in instance A when I click the "Check now" button I get a screen update in about 4 or so seconds with a list of any available plugin updates or Jenkins updates. Fine.
In instance B when I click the same "Check now" button I get "Checking Updates..." which eventually changes to "Checking Updates... Done" at which point I have to click "Go back to update center".
How do I get instance B to behave like instance A?