Composter: The last object wasn't consumed while successfully created the 7th layer.

How to reproduce:

1. Put a composter, and fill it by materials until reaches the 6th layer.
2. Continue filling, slowly. When successfully reaches the 7th layer of composter, you can see that the last object wasn't consumed.

This problem can also reproduced by using hopper.

While using hopper, there're more details.

Reproduce (using hopper):

1. Put a hopper, filling it with 5 different objects.
2. Put a composter under it.
3. Open the hopper, obverse the number of objects.

Finally you can find that while the composter reaching the 7th layer, the 1st wasn't consumed, but the 2nd/3rd/4th/5th object was consumed.