I'm finding that when I move the work stations for the armoursmith and weaponsmith villagers, they become immobile. The villagers will stop where they are and ignore the workstation completely. the work stations are capable of being "picked-up" by other, unemployed, villagers. I haven't experienced this before, and I'm finding it hasn't been posted anywhere yet. When I pick the work stations back up, the villagers move again, but return to being immobile when I place the work stations down.
I'm currently using vanilla tweak, mostly UI and minor texture reworks.