Chest bug/losing item

Hey this is to report bug when your inventory is full and you pick up a chest all the items inside disappear,also on that note due to the bug I lost my early acces helmet I was wondering if there was a way for you guys to recover that for me my steam ign is TTvNastyNateBrrr thanks for your time.( I have all 3 other pieces it was just the helmet I lost)