Noticed the same behavior. No zombie villagers spawn in the world, including from zombie spawners. Starting to realize that, perhaps, zombie villagers now is not the type of zombie, but the type of villager. I'm not sure though if it's a bug or intended feature, but I'd really hope to see zombie villagers roaming the streets at nights in future. In game, of course.
Confirmed! Yesterday, when I first upgraded server to 1.14-pre1, I played normally. Today I cannot join the server (with server being crashed) because of this bug.
Noticed the same behavior. No zombie villagers spawn in the world, including from zombie spawners. Starting to realize that, perhaps, zombie villagers now is not the type of zombie, but the type of villager. I'm not sure though if it's a bug or intended feature, but I'd really hope to see zombie villagers roaming the streets at nights in future. In game, of course.