There is a conflict between something ordered in my preliminary divorce agreement and the final decree. Which is the correct one to be assumed?

I am divorced. In my preliminary hearing, it was ordered that medical expenses run up by my ex spouse pertaining to my children that I did not agree with, that I was not responsible for paying. When the divorce finalized, no such wording appeared in the final decree. My ex spouse is now asking that I pay a medical bill that came up in the time between the preliminary agreement and the final decree. Am I responsible for it?