Site name repeats in browser bar title at the end of title

Hi I am seeing the site name repeat at the end of the title on all pages on a specific site for instance at https://www.ruthlessambitionthebook.com the title in the browser bar up top shows as Ruthless Ambition: The Rise and Fall of Chris Christie by Louis ManzoRuthless Ambition

Not good, would be ok with a space and a dash, I’m not sure if the theme is doing this or a setting in Yoast. Probably something very obvious, anyone have an idea?

Thanks

https://www.ads-software.com/plugins/wordpress-seo/