Since you have a G account, you can disable the login in the settings on the accounts page.

@Terry

Um, well, no. I never surf while logged into any service to prevent data-scarfing. I see that message while not logged into Google.

This can possibly be the consequence of using Total Cookie Protection that isolates (partitions) cross-site cookies and uses a separate cookie jar for each website you visit.

• https://support.mozilla.org/en-US/kb/total-cookie-protection-and-website-breakage-faq
• https://support.mozilla.org/en-US/kb/introducing-total-cookie-protection-standard-mode

Selecting "Cross-site tracking cookies" sets network.cookie.cookieBehavior to '4' and does not partition/isolate cross-site cookies, but still keeps Enhanced Tracking Protection enabled.

Selecting "Cross-site tracking cookies, and isolate other cross-site cookies" sets network.cookie.cookieBehavior to '5' and enables Total Cookie Protection.

@cor-el

Funny, when I read your answer, I thought that 4 would be the solution, albeit with worse privacy, but 5 is actually the solution. And when I looked at Settings->Privacy&Security, my initial settings of Cookies->all-third-party-cookies and tracking-content->all-windows remained as I set them, so there's no reduction in privacy.

Thanks a bunch for that.

Never mind. When I powered-up my PC this morning, "Cross-site tracking cookies" was set to 0 (zero). After some cursory testing, I found that it resets with every restart of Firefox