Be careful with clearing history when Firefox closes! (Clearing browsing history will prevent Firefox from restoring open windows and tabs and retained saved tab groups.) Does that match in the "Firefox suggest" list have a blue star on the site icon? If so, that could indicate that there was a duplicate bookmark to the page. Call up the Library window using Ctrl+Shift+O (as in Organizer), then use the tiny search box at the upper right to find the bookmark and delete it from the results list. If there's no star, it probably is a history entry, but with your settings, I don't know why that would be there. You can check by calling up the Library window using Ctrl+Shift+H, then using the tiny search box at the upper right to find the site in your history and deleting the individual visits from the results list. Any improvement?