RE:Suncor loses $609M in Q3Loss is due to a revalue of assets based on the price they just paid for a larger % of the same asset. It is a non-cash loss and likely should have been booked long ago if this is the current price. Either that or maybe they got a steal of a deal from Tech that wanted to get rid of some assets.
If they just bought an asset at a good deal it sucks to have to show a loss but them are the accounting rules. Maybe it is better than the results depict.