Site name in results of Google (not in title)

Hi all
I read dozens of threads but no mentions my problem.
When I insert an article or a page on WordPress these are immediately pushed on Google.
The problem is that Google added to the end of the title the name of my site. I use as Yoast plugin for several years now and of course I deleted the metadata of the titles (sitename) and work perfectly on the site but not on Google. Google not only place the name of my site but also includes it in the wrong way! Please look yourself: https://www.staseraintv.uno (Try any item) The name of site is “Stasera in TV” while Google enters “Stasera in tv” that does not even exist on the site. The only part of the site save are the pages. I do not understand why. The only help I can give you is that this phenomenon began after the last update of Yoast