Since 23.09 the upgrade system has (finally) switched to requiring the use actively select the new repo branch in order to upgrade. That prevents accidentally pulling packages from the new branch before upgrading for example. The dashboard check update check can now check all available repo branches so it show an upgrade there.
Once you have selected the new branch you can then upgrade from the console in the normal way. There is no way (currently) to switch the repo branch from the CLI.
There is an issue with some pkgs in the new upgrade system if you're running ZFS. The new system creates a new BE and runs most of the upgrade process in to the new BE before rebooting which allows much shorter downtime. However some packages have to run their install scripts after the boot and currently they try to do that before the network has finished configuring. That results in connection failures if they try to update signatures like that: https://redmine.pfsense.org/issues/15396
The new version of pfSense-upgrade reports the status check more accurately. At that point, immediately after upgrading, pkg may still be running in the background completing package installs etc. Until that finishes the update check cannot run and correctly reports the check data as invalid. As soon as the other pkg processes complete it will check and show the update status. In previous versions it would show
the system as up to date there even if it was actually unable to check.
So it sounds like everything you saw is expected.
Steve