Cant cancel properly ender dragon spawn with CreatureSpawnEvent

Expected behavior

After canceling the spawn of a dragon from CreatureSpawnEvent, a bossbar should not appear since the dragon's spawn is canceled Note: Nether portal is cancelled, only the end portal is not.

Observed/Actual behavior

After canceling the spawn of the CreatureSpawnEvent dragon, a boss bar appears, and the event is canceled (the dragon is not spawn but regardless a boss bar appears)

http://prntscr.com/121u9mc

Steps/models to reproduce

@EventHandler

protected void onDragonSpawn(CreatureSpawnEvent event) { if (event.getEntityType() == EntityType.ENDER_DRAGON && event.getLocation().getWorld().getEnvironment() == Environment.THE_END) { EnderDragon dragon = ((EnderDragon) event.getEntity());

    dragon.getBossBar().removeAll();
    dragon.getDragonBattle().generateEndPortal(false);

    event.setCancelled(true);
}

}

Plugin list

FastAsyncWorldEdit-Bukkit-1.16-655 HolographicDisplays Multiverse-Core-4.2.2 ProtocolLib

Paper version

This server is running Paper version git-Paper-756 (MC: 1.16.5) (Implementing API version 1.16.5-R0.1-SNAPSHOT) You are running the latest version Previous version: git-Paper-a98d389d1 (MC: 1.16.5)

Agreements

[X] I am running the latest version of Paper available from https://papermc.io/downloads.
[X] I have searched for and ensured there isn't already an open issue regarding this.
[X] My version of Minecraft is supported by Paper.

Other

No response

PaperMC / Paper