What I expected to happen was that a single hopper would fill the whole double chest. I heard that you can fill it completely by placing another hopper facing the other side of the chest. It is probably a bug about only filling the side of the chest on which the hopper is depositing
What happened was that I put a hopper connecting to a doublechest and it only filled it halfway and stopped flowing items
Steps to Reproduce:
1. Place a chest.
2. attach a hopper underneath it
3. Place a doublechest under the hopper
4. fill the doublechest quarter-full with items (to make the process faster)
5. Fill the first chest completely with items. (Preferably nonstackable ones to make the process faster)
6. once half the doublechest is full then the hopper will stop flowing items to the chest.