Unexplainable entity spawn delay

Plugins Plugin Development
1

Hello,
I’m trying to create Holograms that show the amount of damage that a player takes.
For that i spawn an Amourstand and change the Name. Now the Unexplaineble:

If the player gets hit the amourstand spawns perfectly at Time but if the Player get damage by a mod item
there is some delay till you can see the amourstand.

The event get called without any delay.

Any Ideas where this delay comes from?

2

It could be that the modded item also fires an event like onUse or something like that, if your computer is not so strong, it may take longer for the armourstand to spawn.
With what modded item from what mod do you hit the player?