Put the summary of the bug you're having here

While playing with the newest snapshot I attempted to create an automatic furnace system. I had a vertical setup of hoppers, furnaces, and chests in the following order top to bottom: Hopper, Furnace, Hopper, Chest. The bug is that the coal i put in runs out instantly no matter how much i use. for example after 2 of what ever was cooking a 64 stack of coal would be gone.
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. Place hoppers, furnaces, and chests as shown in the screenshot
3. Put raw food or ore in the hopper
4. See the bug

*Just to point out it did not happen every time, out of 10 tests it happened 4 times