Google have not made any significant changes to their algorithms to identify duplicate content. For many years, they remain relatively stable. About it said chief engineer of the Google Search Ranking Team Paul Haar.
Obviously, we make improvements to our code over time, including the dup detection. But that's been mostly stable for years.
— Paul Haahr
And recently, a member of the Google search quality, Gary Illyes also told when the results may seem more than two results from the same website. This happens in case if the quality of the other results is much lower.
DYK usually when you see more than 2 results from the same site in the SERP, that's because other results score much lower for the query?
— Gary Illyes
Google does not impose sanctions on sites, if the site hosts duplicate content in different formats. According to Gary Illyes, webmasters generally do not have to worry about duplicating content on the site.
In 2014, John Mueller has told of how search algorithms index and display the results in the duplicate pages of the same website.
