This is less a bug, more of just an issue that can easily be fixed. Since 1.14 and the revamp of villages, all farmer villagers use composters to do their job, no problem there. However, since a villager can be on any side of their work station, including on top of it, this creates a problem with farmers specifically. Since almost all farms have the composter positioned adjacent to farmland blocks, and usually one Y level higher, often farmers will stand on top of their composter, do their work, and then step off, falling onto the farmland and trampling it. This is very annoying, especially since farmer villagers cannot re-till land into farmland. I would suggest making it so villagers cannot trample crops. 

What I expected to happen was...:
Villagers should not be able to trample crops/farmland when descending a single block height onto it.

What actually happened was...:
As stated above, farmers will commonly trample their own crops.

Steps to Reproduce:
1. Find a village with a farm and a farmer 

2. Eventually the villager will jump down from the composter and trample the farmland.