Steps to reproduce:

• Create a 2x2 drawer, give it a stack downgrade (for testing, upgrades also work) and a void upgrade.
• Assign multiple slots to an item
• Insert (pipe, hopper, etc.) more of the item than fits in a single slot
• The drawer voids additional items rather than using other slots.

Additional dirt in the hopper was being sent to the drawer and voided.

StorageDrawers-1.16.3-8.5.2.jar
Minecraft 1.16.5
Forge 36.2.34

Still an issue in latest version:

SD: storagedrawers-1.20.1-12.0.3
MC: 1.20.1
Forge: 47.3.0

Fixed in 12.0.4