The villagers can't loose their first chosen job. I destroyed the block they were linked to right in front of them, at different daytimes and different locations (outdoor and indoor). After giving them a new workstation right in front of them they will not claim it, even if it's their old working station. And if they have a station on which they are working: Sometimes they will not use it after a while.

And 1 villager wasn't able to claim a bed despite of more than 1 free option. He just stands and walks around the whole night, another villager was tested and he claimed all of the beds in a row immediatly after destroying his chosen one.

(hope i explained it well enough)