Minecraft wiki entry for Development_versions, associated text: Villager workstation logic changes.
Villagers no longer try to work at the same workstation.
When a workstation is placed, the most experienced nearby villager for that corresponding profession gets the workstation.
Villagers now have to walk to and reach the workstation before they can acquire the profession/work there.
Villagers check and make sure their workstation is valid at all times of day as long as they are within 16 blocks of their workstation.
The experience bar now accurately reflects how much experience villagers have and need.
Clocks and compasses no longer function in the villager trading UI.