I have no reason to deactivate the plugin prior to updating it and have never done so. The only reason I deactivated the plugin is to reinstall the Pro version as per your instructions above.
The license is registered on both sites with this problem in the MapPress settings. The other site is https://pecstudiotour.com/map-of-studios/
I have been using the normal auto-update settings, but have now disabled auto-updates on this plugin, because I don’t trust this not to happen again.
I’d be happy to give you access if you want to take a closer look.
The description shows on Chrome but not on Firefox. Here is a screenshot using Firefox 95.0
