Snippet Preview doesn't change

I make changes to the SEO Title and the Snippet preview changes, but when I save the page, the part I removed comes back.

I have checked the Rewrite override box, but that made no difference.

This page is the home page and the behavior seems limited to that one page.

I don’t know where the Snippet pulls the site title from that can be changed. Any suggestions or pointers to the instructions would be much appreciated.