Amazon often lags behind in changing pricing for rebates. That happens at both ends - when I bought my 7D, I wanted to buy through Amazon since I had a few hundred $ in gift card balance - thanks to a post here on CR, I was aware of a $100 rebate the day before it went into effect, and the next day I went to buy but the rebate had not been applied. I called Amazon, they verified the rebate and applied a discount to my order, but their website didn't actually reflect the rebate for another day.
Also note that even post-rebate, prices didn't go all the way back up. For example, the $400 rebate on the 5DIII+24-105 kit ended, and the B&H in-cart price went up only $100, from $3500 to $3600.