188.8.131.52 Beta, 1.16.20, 1.16.40 Hotfix
Mobs doesn't suffocate on farmland/grass path, this was fixed in the latest Java Edition version.
Step to Reproduce:
1. Build a mob chamber and place down sticky piston with farmland/grass path in front. (like in the screenshot)
2. Put any two-block tall mob into the chamber.
3. Turn on the sticky piston.
-> Mobs doesn't suffocate inside grass path/farmland.