According to the minecraft gamepedia, "In Bedrock Edition and Java Edition 1.14, Villagers can change their profession." but this does not seem to be the case.

I am playing pre-release 5 with my friend in a LAN server and we have an abundance of fisherman villagers. This seems to be due to two specific problems.

First of all, our villagers have claimed workstations that should not be possible to claim. They seem to have detected and claimed barrels in a bunker well over 30 blocks down underground. I assume this is a bug, as I've been told that villagers are only meant to claim workstations within eyesight. 

The second issue is that these fishermen refuse to switch to different professions. We've not even interacted with them yet. let alone traded, but they remain in their profession even after the barrels are removed and new workstations placed elsewhere. Even more interesting is that the fishermen are within eyesight of unclaimed cauldrons and grindstones, yet refuse to claim them.