"it contains hydrogenated soybean oil, the ingredient list also says that it has 0 grams transfat"
That is almost certainly scientifically incorrect, but it's probably legal to say it if the listed portion size contains less than 0.5 g. It is theoretically possible to totally-hydrogenate oils so there is no partially-hydrogenated (trans or cis) component left, but most unlikely in manufacturing practice.
In Canada, the label is supposed to use the legal phrase "no trans-fat", to mean a transfat level below the level which our government arbitrarily sets as being 'insignificant'. Just like our "ice cream" no longer has to have any cream in it ...
