The compacting chest allows players to duplicate items that can be compressed. This happens when the final item (of 4 or 9) is placed in a different slot from the others. The chest then compresses it but leaves all other slots of the item intact. This can also be seen in the screenshots below.

To Reproduce

• Have more than 9 of an item that can be compressed.
• Add 8 in the compacting chest, in one slot or split upon multiple slots.
• Add all remaining items in another slot

Expected behavior
All 4/9 items should be compressed without leaving any behind.

Version
All of Fabic 1.5.1 - Spectrum 1.5.0