Foxes which trust a player will attack chickens and rabbits when the player leaves and rejoins the world.
Steps to Reproduce:
Spawn two foxes
Breed them
Run this command:
/data modify entity @n[type=fox] Age set value 0
Spawn chickens/rabbits around the fox
→ ✔ The fox will not attack the chickens/rabbitsLeave and rejoin the world
→ ❌ The fox now attacks the chickens/rabbits
Can confirm, and doesn't seem WAI