I noticed that most vehicles in the Winter do not have the same amount of vapor coming out of both exhaust pipes. I understand that some exhausts are not true duel exhaust therefore presume that this question applies only to true duel exhaust vehicles. What would cause this in true and fake duel exhausts?
Most "dual" exhausts aren't true dual exhausts. They are dual tipped exhausts. This means there's one pipe coming back from the engine, then feeds into a muffler and then out to two separate tips. Usually, there's less back pressure on one side than there is the other. The exhaust follows the path of least resistance.
If they are true dual exhausts, they will flow the same. "Same" meaning, you won't be able to detect the difference with the naked eye (there may be slight variations, but nothing perceptible).