just to make sure did you double check the settings on Privacy and Security , section Passwords in the firefox settings?

I checked these at least three times front to back. I have been using these features for years.

I checked all those, they are unchanged from prior settings. Also, suddenly now, I leave websites such as gmail or audible.com, where I had been signed in, and I try to clear my browser (as I have easily and successfully done for years), by going to Firefox's Privacy and Security, and clicking on Clear data button as well as Clear History. But when I return to those sites, I am still signed in. No login is required, for the first time ever (using these routines). This is very troubling to me, a big privacy concern, as it seems there are persistent cookies tracking my other browsing behavior, when I have explicitly (supposedly) cleared all cookies. It seems like Firefox's behavior is suddenly different in a couple important respects, unasked-for and not signaled to me, and without a way to go back to prior functions.