When Piglin Brute get spawned with egg it should not despawn, but when players unload those chunks they will despawn. They don't despawn when they are generated in a Bastion so it would make sence if they don't despawn when spawned with egg.

1. Spawn Piglin Brute with egg
2. Type command e.g. /tp @p ~ ~256 ~
3. Type exact same command but with "-" in front of a number e.g. /tp @p ~ ~-256 ~
4. And Piglin Brutes that are spawned with egg will disappear