items disappear from toolbar WITHOUT armor breaking

I read the comments for bug MC-15416 and the linked duplicates but none seem to address a situation where the item simply disappears without fighting or armor breaking. I was simply walking and the item disappeared (brand-new lvl 30 enchant bow). I pulled another (full health) bow from a chest and the same thing happened. I pulled a bow with approx. 80% health from the chest and proceeded to kill what needed killing. Then I returned, replaced the 80% bow, created a new bow, and had it disappear almost immediately. After reading the bugs I checked my armor - I still have it all, none of my armor items are broken.