I blame this on an UX blunder.

Bluesky users are taught not to enter their Bluesky passwords to enter different apps, but rather create a different "app password" for each one. Then Frontpage went OAuth which directs users to Bluesky login page. Bluesky brings us a different login page for OAuth use :/ and obviously does not remember that we are already logged in in the same browser.

This of course means that we have to enter a Bluesky password to a slightly different-looking website - a somewhat fishy way to authenticate a user...