Initially, while testing the new villager farming AI, the farming villagers both planted and harvested crops as they should. However, after a little bit of time had passed, the villagers stopped harvesting fully grown wheat, although they will still plant wheat if you give them seeds.

However, a different, smaller farm (with a single villager) is still fully functioning even though it has been functioning for a longer period of time.

I will attach screenshots of both the larger farm with multiple villagers in it, and the smaller farm with only a single villager in it.

Edit: After a bit of testing, is seems that this issue is caused by the villager's inventories filling with wheat. This is still an issue, and not working as intended because villagers never seem to drop or dispose of the wheat they carry, so they will never farm again.