Notes: we are using the fabric version of the mod for 1.20.1. Initially noticed with with 12.10.2, just updated to 12.10.3 and it did not resolve the issue. Drawers that are full with void upgrades will not take items from "automatic inputs"
-I've tried different methods using tom's simple storage inventory hoppers/cables/terminals, modern dynamics pipes, simple vanilla hoppers. In these cases, nothing gets taken out of the chest the items will just sit there.
-Similar results if I try and deposit items from the toms simple storage terminal, except it just finds a chest with an opening instead of acknowledging the void upgrade and voiding the items by putting them in a drawer.
-if the drawers are not full, they take items as expected so we are assuming everything is connected and working as intended otherwise, we are trying to pump items into the front of the controller (the side with the downward pointing arrow on the top half), not sure if that matters..
-If I manually right click on the drawer controller with a stack, the items will be voided as expected.

This seems to not affect any Forge or NeoForge versions, so if I followed your steps correctly, it must be exclusive to Fabric.

Seems to be related to #1172

Seems to be related to #1172

Just a couple notes since it was mentioned in the other thread.
-We do not have create on the server, so definitely not a create specific issue.
-And in the other thread, someone noted that issue should have been resolved on 12.10.2 of of the mod but it appears to be present on that and 12.10.3 of the versions for fabric. At least as far as non-create interactions stand.

I'm using version 12.10.4 on fabric 1.20.1. Vanilla Hoppers and create seem to work. But ae2 seems to ignore a full drawer, regardless of priority