If you use the command createVehicle it produces at the first time a massive performance usage of the current class you spawn.
The milliseconds to spawn it are 4 - 70 times as long as after the object is spawned once.
The issue cases every object if you spawn it for the first time.
The issue is client side for every player, hc and server.

So an example, if you spawn this class "B_Plane_Fighter_01_F" in VR on the debug consol with createVehicle it takes for the first time more than 6.8 ms, after it was spawnt and delete or is staying there, the next 100 spawns it is between 0.9 - 1.2 ms.

I think maybe it has to do with the class init event handler, but why is it only on the first spawn?

For mission makers who create missions, like CTI, where you spawn and despawn a lot of objects to balance the FPS on the whole map, it is important to not have a massive lag, when a objects spawn who was not on the map.

My workaround for round about 3 years is to spawn the most objects I use in the mission once time client side, so I don't have the massive spawn lag.