It has been a while since i took a look at the Google Search console. Unders structured data i found today 106 errors and all of them are related to “Missing author” problem. It shows the problem started nearly a month ago which is about that time we switched to GPP.
I use Yoast SEO on my site and on their page Yast says that it is theme related issue. See here https://kb.yoast.com/kb/fixing-hcard-author-error/
Any advice how to fix it?