All of the villagers and iron golem in my town are suddenly gone. I started with two villagers that I escorted via mine cart from a nearby village. I bread them until I had about 30 villagers. The iron golem naturally spawned to protect them. I've had no trouble with any of them for the roughly 30 Minecraft day cycles they've been around for. My entire village that I created from scratch and live in is within a massive double wall. Everything is well lit. Not a single animal in any of my farms are missing. Only the villagers and iron golem are gone. Every villager has a bed.

I went on a trip to collect fish at a nearby coral reef, and the game crashed about 15 times within a half hour. Typically, it only crashes about once per hour. When I came back, there were only two villagers and no golem. I immediately quickly went inside my house to get bread for them to breed and restore the population, but when I got out of the house, only one of them was left. I was gone for under 30 seconds. It was the middle of the Minecraft day.

Probably about 5 of them were villagers that I actively traded with.