If you are using separate page as a homepage then setup title and description from that place. Sometimes when did it with separate page so Google already crawled old default homepage title description also and your separate page both so after make the homepage changes Google takes time to show their fresh version. Secondly Go to Settings > General and remove the default title and tagline that is the default WordPress homepage title place.
OR Go to Yoast SEO > Titles & Meta > and under the Homepage section setup your homepage title and description only if you are not using separate page as a homepage. Otherwise separate title and description inside your page Yoast settings.
Hope that will help you!