Mobs holding items which they picked up still despawn in Peaceful

This results in the complete deletion of the item, which is obviously undesirable. Most cases like this (e.g. curing zombie villagers) result in all such items being dropped here, so this is one potential fix. Either this, or persistent mobs could be made to not despawn in Peaceful in the first place (perhaps with passive AI) since they're intended to not despawn at all.