A player on my StoneBlock server brought to my attention recently that rotating the a wrench would cause all contents of the furnace to vanish. I tested on the server to see if it was an isolated incident, it was not. I created a fresh instance with only More Furnaces and Thermal Expansion to test if it was another mod causing the issue.

To recreate

1. Place any type of Furnace from the More furnace mod
2. insert Fuel into the Furnace
3. Rotate furnace using a wrench(tested with crescent hammer from Thermal)
4. Check furnace post rotation to find Fuel is gone.