Robert_Charlton - 4:46 am on Sep 24, 2012 (gmt 0)
IanCP - Looks like you're redirected just fine. I can't speak to the rest of your canonicalization, but the www subdomain certain appears to be handled properly.
It may have been a glitch, but I wouldn't lose any sleep over it. If you do a search on the email text and see that lots of others are receiving the same note, then it might be a glitch on Google's end, or else a classic bit of unclarity.
Maybe this is their new way of telling you that everything's OK. ;)