Do you mean your front fog lamps go off when you select reverse? Why is that a problem? Front fog lamps are to help you see the road immediately in front of the car in really thick fog at night (unlike rear fog lamps, which are to ensure you are seen, but dipped headlamps do that at the front). If you are reversing, you will be looking backwards, not forwards.
Or do you mean the daytime running lamp doesn't illuminate unless you are in reverse?
Or do you mean you have a red rear fog lamp on the driver's side, and a white reversing lamp in the same position on the passenger's side? The 2015 Mondeo only has a rear fog lamp on the driver's side, which is a normal cost-cutting measure used by many car manufacturers as there is no legal requirement for a fog lamp on the passenger's side. Similarly there is no legal requirement for two reversing lamps, so many cars only have one which can be placed on either side.
Normal, no. You need to check all the lights and get back if others are also lit but maybe only half lit. Your back up light might have a bad ground and it is looking for a ground finding it in the fog light, in doing so also lighting the fog light. Stranger things have happened.
Hi yes as this is now the law as you need daytime running lights since 2011.
NO !…..Of course it isn't !
It's still under warranty. Take it back to the dealer.
Dr Bearsface………….You are truly losing the plot !