Mac Desktop Safari/Google auto fills search bar with previous search subject

For a few weeks now on my mac desktop when using Safari when ever I type a new search topic in the google search bar the previous search topic automatically populates the search bar, it's annoying. My system is up to date and Safari is up to date. None of the auto fill boxes are checked in Safari preferences. I've tried unchecking all the search boxes in the Safari preferences, and I've logged into my google account and adjusted my preferences to not auto fill too and nothing works. This is annoying, not sure why is suddenly started doing this.