There's so many tickets regarding broken villagers it was hard to choose the best fitting one.

Up to 1.16.0.60 the villagers were reasonably okay, bugged but workable, you just had to be very careful. 

2 bases containing villagers - Base 1 cures zombified villagers and sends to Base 2 through Nether. In the curing base villagers link to workstations ok but upon entering base 2 they link to beds but won't link to workstations at all so won't refresh their trades.

Not sure if there is a cap on cured villagers but I'm using around a dozen or so...

HTH