Ivan Isovich
Comments
This appears to be sphereacle, so going mining at diamond levels almost immediately moves you out of range of surface farms. I agree this is too small.
Ticking areas help, but ultimately, the render distance of mobs shouldn't link to the growth of farms or entities. This is also affecting how mobs despawn, as they move off the edge of active areas and freeze. If you stay in a small area, this freeze affect causes massive buildups of mobs, passive and hostile.
I have noticed the weird spawning issues. I have not seen mobs spawning in high light levels at night. My friends and I play on a Realm extensively at night in a well lit area and have had no mobs spawn there.
However, in the nether, there is a ridiculous number of mobs still around. I love the high mob cap, and that should stay the same, but I think there is an issue with random despawns.
One of the issues is the way mobs move out of active areas. I've noticed that since this is different from Java, and mobs will actively move up to about 60 blocks away (whatever their visual radius is from the player), this allows them to move into inactive areas and freeze. When the player approaches that inactive area and makes it active again, there can be huge numbers of mobs. I have also seen this with ticking areas, where the mobs move out of the ticking area and if that area is not approached by a player for many game days the mobs build up to high numbers in the edges of the ticking area.
We use the nether as a hub between different areas, and can hear absurd numbers of ghasts. I found an area near a fortress that was a bit of a valley where dozens of mobs had fallen and weren't despawning.
And, just as posted, a newly generated fortress was cleared, and no mobs spawn in it except at blaze spawners.
I had this happen on a converted world (not sure if that's what you meant by "synced" world). Had to use cheats to restart the spawners (using Realms). The strange thing is that when I first encountered a spawner, it worked. It was in a previously generated area, but we had not found it yet. 2 were about 50 blocks apart and both were working, then a few days later were no longer working, and no mob was featured in the spawner cage. Breaking the spawner and replacing it fixed the issue.
Noticed this is true on Win 10, Realms. Could not figure out a pattern as to when they attack. Was able to approach multiple blazes by a spawner, and they did not do their short range melee attack, either. Then, one would randomly display the fire particles like when they are supposed to aggro, and shortly afterward they throw the fireballs. (and most of the time, they get an insta-kill as reported in another bug). The others did not aggro, as they are supposed to do.
I have been watching this issue in my Realm. I have narrowed the problem down to villagers are not loading when they are standing on plowed dirt. I have had a pair of villagers consistently in a 8x8 area that is sealed off and lit, and when the ground was tilled, they were constantly despawning (most likely during the game load, as this area was set in a ticking area). I would summon two more and test other things...like were they falling through the tilled ground (no), getting stuck on a ladder (no), or having mobs spawn there (no, one would be left sometimes b/c there is a strip of cobblestone that he likely was standing on but the other was on plowed ground).
Similarly, cannot throw a potion through a half slab opening, and when it hits next to that block, the splash affect doesn't pass through the half-block opening.
@joe smith: This was more of an addition to your bug report with some observations of my own. The mob spawning is working on our Realm (other than how we get overworld mobs like spiders and creepers spawning in the nether, plus no mobs in nether fortresses), playing on normal difficulty, so doesn't seem to be a universal problem but no less important.