One is probably a release date and the other is a street date. I don't know why stores do this, but usually a release date is a day before the actual street date. The release corresponding with when a store should get the product, and the street date being when it can be sold. The other issue could be if the product was released a day earlier or later in Canada, so it could be confused by that, but I'm pretty sure its the first issue.

Check a calendar for the year and chances are, whatever day is Tuesday is the games actual date it was released to be sold.