I've setup 2x2 drawers for Mystical Agriculture seeds. 3 slots for the produce and 1 slot for the seeds. I've added a storage upgrade V (32x) and a void upgrade.

I found that the produce got voided if the first slot was filled to the max, ignoring the other two slots (the single stack I put there myself):

framedcompactdrawers-1.16-2.2.1.jar
Minecraft 1.16.5
Forge 36.2.34

Does this happen with regular drawers too? This mod doesn't (in theory) touch any of the item handling code and just inherits it from regular Storage Drawers.

Make sure you're also using the latest Storage Drawers.

It does, I should have tested that first.

Raised jaquadro/StorageDrawers#1023