I previously made a report about excessive breeding amongst villagers. In that report, I mentioned how 62 villagers somehow became 149, but I couldn't figure out how enough disappeared that any of the 51 beds was unclaimed. Well, now I think I know why.
Today I farmed my crops, which are located in fields close to my main village, close enough they the village could render, depending upon where I was standing. After going through all of the effort to farm 3072 wheat crops, 3072 collective carrot/potato/beetroot crops, 16 stacks of sugarcane, and many stacks of pumpkins and melons, I was about to go start trading. But then my game crashed.
I have several saves of this world now, so I know there should be 62 villagers. But when I revisited my village after the crash, I found 29 villagers, so 33 apparently despawned, more than half the population.
I've had several other crashes that I thought might be mob-related, where mobs get deleted because of the crash. In this case, however, I think there is strong evidence that loading/unloading the villagers a certain number of times may have caused the crash, since I would have been rendering the village repeatedly as I harvested my crops.
Related issues
Comments
migrated
GoldenHelmet
This kind of random despawning is tracked at MCPE-21416, so this ticket will be resolved as a duplicate. However, I am also interested if you can share any details about where (coordinates or distance) the villagers disappeared from in relation to where you were when the game crashed or when you reloaded. Also, your simulation distance And render distance.
A bit of advice: it does sound like you have quite a lot of farms and a very large number of villagers, and that could be straining your system and causing the crashes. Villagers can cause a lot of lag when pathfinding to their workstations, or sharing food back and forth (see my comments on REALMS-3089). Reducing simulation distance or render distance might help with stability in your world, as might some strategic redesigning to constrain or guide villager movement.
migrated
This particular village is literally 40 blocks or so southwest of the world origin. It also contains the world spawn point. If you're interested, the seed is -1668452317. My farms are in the small plains biome just to the east of the spawn; they are about 60-70 blocks long east-west and 100-110 blocks north-south (I did some terraforming, but the largest flat area is where they are primarily). A shack with barrels, a bed, and a grindstone in it is next to the western end of the farms, on top of a natural hill maybe 20-30 blocks from the treeline. I had to put a fence in just outside the taiga to stop villagers from trying to invade the shack.
My simulation distance was 6 chunks, and my render distance was 9 chunks.
Also, the "artificial" structures are on the west end of the village, so they wouldn't have extended the village east.
GoldenHelmet
@Tim D.: Just looking back at your report again. Thanks for the additional information. With sim distance 6, when you are at one end of the 100 block area, the other end is not ticked. If you spend a bit of time at one end or the other, that would explain why overbreeding occurs (MCPE-47212). I suspect the overpopulation is what caused your crashes, because that is known to happen with large accumulations of mobs. The crashes would then have caused the mob disappearances (MCPE-21416). It's actually hard to say how many villagers you had, because you would only have found the ones that survived each crash.
Previous report:
MCPE-81943