I've been working on an enormous castle/village for weeks on solo survival.
I spent some time a few chunks away from it to build an iron farm, and when I came back to my castle, everything was gone.
I had a stable with over 30 saddled/armored horses enclosed, my entire farm of pigs, cows, sheep, llamas... Every dog, every cat, every ocelot and golem, sitting, roaming or tethered...
I had an armory with 36 armor stands, much of it with fully enchanted diamond or netherite armor...
All of it just vanished...
I'm now faced with the decision to go back to my last backup of the world and lose a weeks' progress, or go back and spend countless hours getting all those animals/materials back...
WTH!?!
Same issue as of 10/20/21
all the fish I place in my aquarium get bleached white, all color gone.
currently on 1.17.40