Hello, using Limited barrel IV when setup initially without any upgrades, bottom right slot is to be filled with any compressible item.
Then the top right with any item, and the top left with any other item.
You can then click on the face of the barrel to insert a compression upgrade.
After this when the item in the bottom right is inserted into the barrel by any automation, it compresses properly, but causes the item in the top right to be completely consumed and converting into the top left item, sometimes in higher quantities.

This overall would allow conversion of low value materials like dirt to other higher end materials using the drawer.

Mod version
sophisticatedstorage-1.18.2-0.8.53.669
sophisticatedcore-1.18.2-0.5.106.502

Adding that in this instance it was the compressible item being imported into the barrel with a Mekanism logistical pipe through the controller block.

I can't recreate - unable to insert compression upgrade into the barrel because of the items in the first two slots. Please update to the latest version and I will need steps I can use to recreate after that.

would need the pack owner to update due to incompatibility with the newest version on 1.18, but compression upgrade was inserted by holding them in your hand and clicking the front face of the barrel instead of using the UI. If thats been fixed in newer updates ill reach out to the pack owner.

it may have been broken at some point, I can't recall because 1.18 overall is really old by now, but I definitely click it in like that in dev.

closing given that this was logged for older version and is waiting for pack owner to update. If you are able to recreate on newest version feel free to reopen.