Villagers gone

Put the summary of the bug you're having here
I loaded up a world from 1.15.2 in snapshot 20w13b and all of my villagers are gone. I went back to 1.15.2 and they were still gone.
What I expected to happen was...:
Describe what you thought should happen here
They would still be there
What actually happened was...:
Describe what happened here
They are gone
Steps to Reproduce:
1. Load up world from 1.15.2 in 20w13b
2. Go to where you keep your villagers
3. They should be gone