This problem is caused by this very bug that Jolla for years has been neglecting to fix.
ssu re is set to the new release version as soon as an OS update starts downloading. If the user then does not apply the downloaded update right away but quits the GUI updater, the device is left with the incorrect release version, which is the source of all those issues. Starting the update at some later time causes this very problem, i.e. request to remove lots of system packages.
See e.g.