When the world was updated from 1.14 to 1.14.1 all my villagers that haven't been traded with yet, but had workstations, all reset to unemployed and would no longer detect the workbench right in front of them. The villagers that had been traded with and were locked in their trades all mixed up their work stations, so they wouldn't restock. I sent them all over 150 blocks away and brought one villager at a time to set them up with their work stations. As I was trying to match them to their work stations they started to not restock anymore, after I've confirmed a workstation for them (i.e. I watched them use it to restock). I let one villager out of their trading cell and they went and restocked from a different workbench that I had already matched to a different villager. So the villagers keep choosing new workstations and won't retain their workstations. This problem was not present before 1.14.1.
Edit: I have done a bit more testing in a creative world, and it seems as though this may be specific to 1.14 villagers, not new villagers that are given jobs after the update to 1.14.1.
Edit_2: It appears that any villager unemployed or employed that updated from 1.14 to 1.14.1 will not retain work stations. I am not sure if they reset each night or if it has something to do with the chunks unloading and loading. I brought an unemployed villager to my trading hall and gave them a workstation, but every so often that id check on their trades without breaking and replacing the workstation, they will have new trades. I still need to test with a newly bred villager in 1.14.1, to see if this problem persists.
Edit_3: I bred a new villager and they continue to lose and replace workstation each night it appears. They continue to reset trades without interaction. Not sure if this is due to the villager being bred from villagers found in 1.14, then updated.
Edit_4: I went out into the world to find a previously unloaded/unvisited village so that it would be newly generated in 1.14.1. I brought back some villagers and bred them. However, even new villagers that I put a workstation next to would continue to get new trades over time, which leads me to believe that in a world updated to 1.14.1 from 1.14, the villagers will not retain their work stations overnight or when loading and unloading chunks (not sure which is causing the villagers to forget their workstations).