This is incorrect. I actually contacted the MFO and this is what they said:
If you ordered your vehicle on or before July 11, 2018, then it will qualify for an incentive provided it is delivered, registered and plated in your name by December 14, 2018 and it was on the list provided to the Ministry of Transportation by Tesla Canada on September 6, 2018. If your vehicle is not on this list, and was not delivered, registered and plated on or before July 11, 2018, it is not eligible.
If you ordered a vehicle on or before July 11, 2018, cancelled the order on or after July 11, 2018, and now wish to reorder the vehicle, the vehicle you originally ordered will qualify for an incentive as long as it is delivered, registered and plated in your name by January 3, 2019 and it was on the list provided to the Ministry of Transportation by Tesla Canada on September 6, 2018.
So this means that if you ordered your car prior to July 11 and it got delivered - say - in October or November, you would still qualify for the rebate (provided you are on the list provided to the government by Tesla on Sept 6th). Also, if you canceled subsequent to July 11th, you can re-order it provided you receive it prior to Jan 3rd.