Villagers links to their job site blocks are unreliable

sistem windows 7

So I made a grindstone for a Weaponsmith. I leveled up the Weaponsmith to Journeyman. I later went to the exact same grindstone which was definitely the Journeymans workstation and instead found a novice. I had thought the Journeyman has died but I later found them alive in some stupid place in the village instead of their original grindstone. The link from a villager to their job site block is weak, and unemployed villagers sometimes 'steal' job site blocks.

This later happened with a cartographer. There is only one cartography table in the village but an old cartographer is now doing nothing during work time and a new cartographer displaced them, effectively stealing their job site block.