The decorations of a sukkah are muktzeh and can't be moved on Yom Tov and this seems to include food items on which no other stipulation was made (which I get from Mas. Sukkah, 10a-b and here).
But if the sukkah is found to have been invalid all along, does the intent of using the decorations as such continue even though the ultimate mitzvah is actually not satisfied? Or do the items (say, food) revert to their natural state of being viable to use on Shabbat or Yom Tov, as they are not fulfilling any role as part of a kiyum mitzvah?
[followup question, pending an answer to this -- what if it is the presence (beyond 4 tefachim of the schach) of the food-noy which invalidate the sukkah, and removing them would make the sukkah valid?]