Villager Reproduction glitch

Put the summary of the bug you're having here

What I expected to happen was...:
To get no emeralds back

What actually happened was...:
I gave the villager a stack of emeralds, and shift clicked, I zoomed out and it gave me most of my emeralds back

Steps to Reproduce:
1. Give a villager a stack of emeralds (if he requests one)
2. shift click the item, get it,
3. Then get out of the trading screen having the emeralds falling out taking away what the price was, but not as a stack.