When I entered my world as usual on version 1.21.72, I noticed that all mobs I had previously interacted with had disappeared.

Tamed wolves

Mobs with name tags (such as custom zombies)

Horses I had ridden or tied with leads

Cows that were tied with leads

Villagers I had traded with

Tridents stuck in blocks as part of farms

All of these entities were safely stored and should not have despawned under any circumstances. The world had been played multiple times on version 1.21.72 without issues before. No crashes occurred, and the game was closed properly the last time.