Infinite diamond generator with hoppers.

What I expected to happen was...:
the diamond going to the duble chest

What actually happened was...:
the diamond stayed in the hopeer and continually putting diamonds in the chest

Steps to Reproduce:
1. place two hoppers near each other.
2. place a double chest below them.
3. put a diamond in the center of the two hoppers
4. the diamond will still float on the top of the hoppers and each hopper will allways have a diamond in it.