I have a lot of "Duplicate pages without canonical" issues with my freeplaysolitaire.com website that are a bit stupid because they're related to the same page .... www.freeplaysolitaire.com and freeplaysolitaire.com with the www removed. I've also had this "issue" reported for http:// and https:// being considered as two different web pages when they're the same page. Ahrefs should be a bit smarter about the analysis instead of going off a checksum of the web page contents and assuming there are duplicate pages when in fact they're the same one.