1. I have cured 6 zombie villagers that spawned in front of me at night. 4 of the 6 had a profession already. 1 of them had a tiny bit of trading xp too. None of them will take other workstations to change jobs. The last one i changed thinks he's a shepherd, but I don't have a loom anywhere (I don't even think I've picked up a loom this world). 

Edit: I tested this in a flat creative world and the same thing happens. No work stations were placed anywhere. I have attached a clip.

Edit 2: This issue was originally noticed on a realm, I have since tested it on a single player creative world and the same thing happened. The video I attached is in the creative world.

Creative reproduction:
1. Spawn in zombie villager
2. Splash with potion of weakness, give golden apple.
3. When zombie villager turns into a villager, it has a profession even though there are no work stations anywhere.

Expected result would be a plain villager with no profession.