Wp site title vs

I constantly run into this same problem everytime I set up a new site.
I will use Yoast, Add Meta Tags.. and select nice perfect custom page titles.
They show up in the bar of my browser window and everything seems correct, then when I see the pages appear on Google.. it’s suddenly grabbing the site title and tagline from within Wp as opposed to the custom title tags being generated.

Anyone know a fix for this in laymen terms?