Hi jaquadro,
first of all thank you for making this mod.
Our family likes to tidy things up and this is the right mod for it.

Versions Used:

Minecraft 1.21.1
Forge 52.0.9
Storage Drawers 13.2.0

Problem Description:

Up until now, we used only the regular storage drawers which work like a charm.
We now started to use the compacting drawers and they don't work at all.
As we are using multiple mods to test, I tried to remove mod by mod to check when it works again.
But sadly the compacting drawers are not even working when the only mod available:

I also tried to create a new creative world with only the StorageDrawers mod as only available and I got the same result:

This got fixed in the NeoForge version a bit ago but got missed for Forge. Should be fixed in the latest Forge release now.