Item frame & armour stands duplication/dissappearing

Item frames will either disappear when loading world or drop when they do appear again, along with anything on the item frame. This has created a number of item dupes I don't necessarily want. As you can see in the attached screenshots, I have a number of copies of the same several maps. Along with a number of crossbows with the same durability in my inventory. 

Armour stands are also behaving like this, resulting in a duplicate full set of iron armour. 

I am not sure how to replicate this bug.