After finding it (multiplayer save) everything looks correct. The item is picked up and spoils in the same tick after picked up. The inserter can’t insert it because there’s already items in the output slot and the inserter that would remove the items are full trying to extract them. Once they are ...

This still occurs on 2.0.32 and can be observed at the "Broken Bioreactor" pin of the following save after about 3-4 seconds.