Foxes which trust a player will attack chickens and rabbits when the player leaves and rejoins the world.

Steps to Reproduce:

1. Spawn two foxes
2. Breed them
3. Run this command:

   /data modify entity @n[type=fox] Age set value 0
   

4. Spawn chickens/rabbits around the fox
   → The fox will not attack the chickens/rabbits
5. Leave and rejoin the world
   → The fox now attacks the chickens/rabbits