Villagers that have been infected by a zombie can despawn, even if they were named before they were converted

The bug

If you name tag villagers and they get converted to zombie villagers they will de-spawn even with them being named when the player goes 128 blocks away from them like normals hostile mobs do.

To reproduce

1. Set difficulty to hard

2. Spawn a villager

3. Name the villager with a name tag

4. Spawn a zombie

5. Let the zombie infect and convert the villager

6. Run /tp @s ~ ~255 ~
   → ❌ The zombie villager despawned