Damage Event Weapon Inconsistency

[Lukadcf]

Expected behavior

I expect that when a Player triggers EntityDamageEvent & EntityDamageByEntityEvent through a melee attack that player.getEquipment().getItemInMainHand() or player.getInventory().getItemInMainHand() will return the weapon used to damage the entity.

Observed/Actual behavior

When attacking immediately after switching slots the new slot will be the mainhand, while the entity was hit with item in the previous slot. This behaviour can be verified by comparing the damage values with the weapon type in the video below.

With some practise this can be easily abused by switching to a slow weapon that triggers an ability within this event. Basically ignoring the slower attackspeed and still triggering the ability.

Steps/models to reproduce

DamageEventWeapon.1.-.Trim.mp4

Plugin and Datapack List

Paper version

This server is running Paper version git-Paper-497 (MC: 1.20.4) (Implementing API version 1.20.4-R0.1-SNAPSHOT) (Git: d8d54d9 on ver/1.20.4)
You are running the latest version

Other

Listeners used in the video:

@EventHandler(priority = EventPriority.LOWEST)
    public void onEntityDamage(EntityDamageByEntityEvent event) {
        if (!(event.getDamager() instanceof Player player)) return;
        player.sendMessage(Utils.colorize("&cWeapon: "+player.getEquipment().getItemInMainHand().getType()+" Damage: "+event.getDamage()));
    }

//Tested seperately

 @EventHandler(priority = EventPriority.LOWEST)
    public void onEntityDamage(EntityDamageEvent event) {
        if (!(event.getDamageSource().getCausingEntity() instanceof Player player)) return;
        player.sendMessage(Utils.colorize("&cWeapon: " + player.getInventory().getItemInMainHand().getType() + " Damage: " + event.getDamage()));
    }