Villagers in a trading center lose their workstations (often without losing their profession), leading to other villagers connecting to the workstations.  This happens even if the villager and workstation are in the same chunk and the player doesn't go more than 2 chunks away.

Checking the villager NBT tags verifies that the original villager no longer has a job site, and the new villager is associated with the workstation.  I have seen both villagers have the same job site, but only after I've used a /data modify... command to assign job sites to specific villagers.

I haven't tried to reproduce in other versions (1.14.1 through 1.14.3) but 1.14 did not have this problem.

Steps to reproduce:

1. Get two villagers associated with workstations.
2. Trade with both villagers.
3. Get an unemployed villager within range of the two workstations.
4. Move at least 100 blocks away (can be vertically so that you remain in the same chunk)
5. Come back.  The unemployed villager will usually have taken one of the professions of the existing workstations.