What I expected to happen was...:
Nothing out of the ordinary. Villagers in trading hall would all still be there.
What actually happened was...:
Every villager in my trading hall disappeared completely so I had to revert back to 20w06a
Steps to Reproduce:
1. Make a game in 20w06a and spawn some villagers, pair them to a bed and a workstation and trade with them
2. Relaunch game in version 20w07a
3. All the villagers will be gone, at least that's how it was in my case.
Environment
Windows 10 64 bit
Duplicate issue MC-172078