It is common, you visit a web site, click through the web pages on that web site and you see that a large chunk of the page has the same content and elements as the rest of the pages on that site. Blocking those pieces of duplicate content is not necessary says Google's John Mueller.
"You don't need to block shared pieces of content on pages -- that's a really common setup across the web," John Mueller of Google said.
Here is the context:
You don't need to block shared pieces of content on pages -- that's a really common setup across the web.
— 🍌 John 🍌 (@JohnMu) May 17, 2019
Again, this is not uncommon and here is Google saying - don't worry about it - it is normal.
To be clear - I suspect this is related to boilerplate content you see often across multiple pages.
Forum discussion at Twitter.