What I expected to happen was:
I put uncooked food into the furnace or smoker, and it remains within the smoker/furnace even after closing and opening Minecraft.

What actually happened was:
Both the items and fuel for the smokers/furnaces are deleted upon the world opening

Steps to Reproduce:
1. Place items into the furnace/smoker in survival minecraft (eg - potatoes and logs to create baked potatoes).
2. While the cooked potatoes are cooking, close the world, then close minecraft.
3. Open minecraft, and open the world with the smokers/furnaces
4. The furnace/smoker texture will remain lit, all of the items inside will disappear