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I'd keep the canonicals in place. Always double-check using multiple sources when you have the ability to do so. SEOMoz crawls and error reporting are great but there are the occasional hiccups. When I logged in and saw that I had something to the effect of 1900 new duplicate content errors showing up, I freaked out too and got worried something went horribly wrong. I looked over a random sampling of canonicals, checked that they were implemented correctly, checked with my web team to see if they made any big changes without letting me know, looked at Webmaster Tools to see what it said, and tried to find answers here in the Q&A as well.. Then I was pointed to this post on the blog http://www.seomoz.org/blog/visualizing-duplicate-web-pages.