gingerbread men cookies getting hard after wrapping

by CONNIE VAGG
(ROSEVILLE CA)

I've used same recipe for years. The last 2-3 years, once the cookies are baked, cooled, decorated...still soft, I wrap each with plastic wrap (always have). Now they are getting hard as a rock? This recipe is unique. It starts with bringing to a boil the first ingredients of corn syrup, gran sugar, cinnamon, cloves, ginger, water. Once to a rolling boil it is poured over 2 cubes of margarine; cooled 30 min, then flour and baking soda blended well. Mixture is goopy, poured into a covered bowl, and chilled several hours. I've never seen a recipe like this. I've changed nothing. The dough is rolled out & cut into shapes, baked, and cooled. Only problem now is, they cool and are soft, but once wrapped turn hard?? Is this enough info to maybe get an answer?