Sitting outside a skelly spawner in SSP and one dropped a golden chest plate w/a couple stats and full health. Getting close enough to pick it up fills all available inventory spots with duplicates.
I've saved the world with the issue, logged back in and it repeats. See attachement, the item in guestion will be right there on the ground in front of you. Check the chest next to me as well, there's a ton more.
Duplicate of MC-10008.