Hello Marc,
I have to correct myself in this case. Originally we came to the assumption that the archiving stopped because phpmyadmin showed the same number of records over several days.
In the meantime, however, it turned out that phpmyadmin with a certain configuration only displays estimated values. Using a SQL count command, however, we were then able to see the correct number, which also increased every 5 min. So the archiving seems to work after all. Sorry for the circumstances.
However, it is still unclear why there are posts in the archiving table that were permanently deleted a long time ago (archived_queued=-3). Has the permanent deletion process not worked 100% here?