My server crashed, and when I logged back in, each of my villagers had been duplicated, with two identical villagers in each trading stall. It seems their trades are shared, as well. When one unlocks the next tier, so too does the other in the stall

What I expected to happen was...:
Each Villager continue being just one villager

What actually happened was...:
Two, duplicate villagers

Steps to Reproduce:
1. It did not duplicate for me. I crashed the server, and the same, duplicated villagers remain.