I see what you mean. If I remove the extension without first disabling it, the context menu items remain. They were gone the next time I started Firefox, so if you haven't already tried exiting out of Firefox and starting it up again, please try that next.

You can also try to disable containers in Options/Preferences (use its search bar). Options/Preferences -> General -> Tabs

Resolved: The Cookie Auto-delete [CAD] add-on/extension needs containers. 'about:preferences#general "Tabs"' has this line: "An extension, Cookie AutoDelete requires Container Tabs", then the checked, greyed-out option "Enable container tabs"

CAD's online documentation confirms that current FF/CAD versions require the setting to be on.

Thanks again