Mod version : 5.3.7
Minecraft version : 1.12.2
Forge version : 14.23.4.2760
Java version : 1.8.0_161 64 bit
Windows 10
Modpack : Stoneblock 1.0.17

When a hopper (or other item movement blocks such as pipes) try to put an item A in a compacting drawing with a void upgrade that already have another type of item B, it trash the item A instead of staying in the hopper like it should.

Note, this seems to happen only with items that have 2 forms (like coal and coal block), but not with items with 3 forms (like cobblestone + compressed cobble of different levels)

Steps to reproduce:

• Place a compacting drawer
• Upgrade the drawer with a void upgrade
• Put some coal inside the drawer
• Place a hopper pointing in the drawer
• Place some diamonds in the hopper
• ???
• No profits, because all the diamonds are gone

Possible issues related to this bug:

XU2 transfer nodes and XNet exhibit the same behavior, even when connected to a drawer controller, as long as there is at least one 2-form compacting drawer with void upgrade in it. I'm guessing they both use the same interface as hoppers to transfer items in. When connecting to a controller, they void ANY items that don't have a matching drawer to go into.

Translocators, exhibit slightly different behavior - they stop transferring ANY items into the system when 2-form+void compactors are present, even when other valid drawers do exist for the items. I couldn't figure out why my translocator feeding from mob farm to drawer controller stopped working, until I found this bug report. Once I removed all the 2-form+void drawers from the system, everything started working properly again.

I found the bug when I saw that my drawer controller was accepting items that had nowhere to go, but I tested and made the report in a way that it show the bug in its simplest form to remove as many random variables as possibles. I have seen the bug happen with normal hoppers, vacuum hopper from mob grinding utilities and enderIO conduits. I have not tested with other way to transfer items.

I am seeing this bug as well. My case is a compacting drawer with 2-form item (coal to coal block in my case) with a void upgrade . If I simply right click any item that is not coal or coal blocks, the drawer will void the item versus reject the item as a normal drawer would. (drawer just ate a fully upgraded tinkers sword in my case ... ugh )