I've noticed that some extensions were tagged as "archived" on mediawiki.org yet their repos were not archived on Gerrit. The similar may be happening vice versa. We should compile a list of extensions tagged as archived on Gerrit and mediawiki.org and join them, then identify which ones are archived in one place and not in the other and fix that anonmality.
T190286 was an instance of this. I suspect we have much more.