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As Brett and Gaston said, this is not ideal, but also not the worst thing. You'll probably have both non-WWW and WWW versions rank for awhile, then Google will start ignoring your canonicals. As Gaston said, it's pretty simple to change canonicals - I would recommend doing that. Otherwise, you're showing Google that your canonicals don't match your actual site, and they may start ignoring them in the future. It's worth keeping your site structure clean! Best, Kristina