Apple menu shows 1 update when already up to date

I installed macos Catalina upgraded on one macbook today. After downloading and before installing I copied the installer package from that macbook to a second macbook, and upgraded it as well. I thought I was doing something smart to save downloading it twice.

On the second macbook, even after installing, the system settings icon shows a (1) red badge and the "software update" section of System Preferences shows (1) red badge. The Apple menu shows "1 update" next to System Preferences menu item. When clicking that menu item, it opens software update, checks for updates, and says you are up to date.

After messing around with it to no avail, I went ahead and downloaded macos Catalina from the app store the normal way, and installed the whole thing again. This caused no harm, but did not remove the red badge or the "1 update" message from the Apple menu!

It seems the softwareupdate part of macos is confused by what I did, and still thinks I have an update to install, but has also already installed it.

How do I get it to sync back up?

Mark