The bug
At the moment, mobs don't save attributes if they turn into other mobs.
How to reproduce:
1)Enter a command:
/summon minecraft:hoglin ~ ~1 ~ {CustomName:"\"Говночист\"",CustomNameVisible:1,Attributes:[{Name:"generic.movement_speed",Base:5.1f}]}
2)Wait for the transformation of hoglin into zoglin
Waiting:Zoglin has the same value of the generic.movement_speed " attribute, Base:5.1f ✔
In the fact: Zoglin has the standard generic.movement_speed attribute, not the set one❌
Note that zoglin saves the name, but not the attribute.
Works with piglin turning to zombified piglins, villagers to witch, turning villagers into zombies and Vice versa.
Linked issues
Comments

Duplicate of MC-88967.