don't know if this goes here, but hopefully will contribute
Happened before, but only tridents dissapearing, this time was massive.
It started when traveling like 5000 blocks or so via nether (600 in nether) in Win10 Edition V 1.17.41.
In the overworld, those were new loaded chunks. It was a Badlands Biome. Single player. Can't say if laggy, I was going under (Y12 in the nether).
went back to homebase via nether and left all loot (gold). By that time all was normal
then went to my creeper farm starting at Y 193... librarian villager base starts at X 688, Y 62 and it's 104 blocks in X away from the center of the creeper farm almost straight forward on Z.
This creeper farm in particular https://www.youtube.com/watch?v=ABJoE9k45bw&t=166s
discovered the minecart hopper was gone. went back and crafted another. all entities were still there.
AFK'd thru the night. Probably 5 hours or so. Everything good. Exceeded the double chest so there was powder floating.
Went down like 3 times to make TNT
Went back to do manual creeper grinding. Letting some creepers fall and slaughtering them with looting III
When I went back, all entities except for 1 tagged wolf and a horse (not tagged) were gone, including several de-zombified villagers, living stock (pigs, sheeps, cows, chicken), cats and stands.
Another curious thing is that it affected all armour stands on the same X coordinate except for 1 leather armor stand. Affected my cat and my girlfriends cats but not her dog, which was closer, but still managed to despawned a couple of horses, which were further than the dog (16 blocks away on X and 5 in Y, not chunk bordered).
Hope it works.
Edit:
I used render distance at 8 chunks while AFK, as it was the minimum the game let me by default.
Not entirely sure if the entities (villagers, cats, etc.) were there when making the minecart hopper, but I believe they were there.
I always close my world via Esc > Save & Quit
World size is 223 MB survival and it's my only world
It worked
Thanks a lot.
I feel dumb now, I didn't knew it hehe