Farmer villagers won't harvest grown crops - they just stare at them

Farmer villagers are not harvesting full-grown crops, instead they freeze and stare at the crop. In pictures 2 and 3 two villagers are trying to harvest a grown carrot through a wall.

This bug occured in vanilla minecraft, no mods, add-ons or anything else is used. Mob Griefing option has always been enabled.

More info:

Check picture 4

At first, villagers seem to start harvesting the farm normally until they freeze.

Steps to reproduce:

1. Find a village (preferably a plains one){}
2. Find a farmer & a farm **
3. Observe the villager harvesting the farm
4. Sooner or later the villager should freeze and stop harvesting anything.