John Mueller said during a Google’s Webmaster Office Hours that some webmasters were mistakenly receiving "new site owner notifications.” When site owners receive this,
the first thing that comes to mind is the site has somehow been hacked and a hacker has added themselves to the Google Search Console account om their account, something that does seem to be happening
more frequently lately, according to Jennifer Slegg. In a Twitter tweet, Mueller told marketers to double-check accounts, but not to panic.