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I work for an agency. Recently, one of our clients decided to do a complete site redesign without giving us notice. Shortly after this happened, Moz Site Crawl reported a massive spike of issues, including but not limited to 4xx errors. However, in the weeks that followed, it seemed these 4xx errors would disappear and then a large number of new ones would appear afterward, which makes me think they're phantom errors (and looking at the referring URLs, I suspect as much because I can't find the offending URLs). Is there any reason why this would happen? Like, something wrong with the sitemap or robots.txt?

So, I've been working on a site for a while, and they recently had one of their blog posts marked as "duplicate content" on Moz Pro: https://ashlandbreastpumps.com/blog/breast-milk-storage-guidelines/ Reviewing this post, there's nothing here to suggest that it should be considered duplicate. Link is marked canonical, there are no weird domain shenanigans to cause confusion, the content is distinct, and there's a lot of content there that prevents it from being overcome by coding white noise (So "more content" wouldn't be a solution here). So I'm trying to figure out why this particular post was flagged. Did Moz Pro make a mistake?