The init event doesn't fire when using the createVehicle script command.
Wiki entry of the event: https://community.bistudio.com/wiki/Arma_3:_Event_Handlers#Init
I attached a sample mission.
It's a VR mission with one soldier added and the soldier init field has:
this addEventHandler["Init", {systemChat "init fired"}]
There is a trigger that can be activated using Radio Alpha.
The trigger runs the following piece of code:
_box = "Box_NATO_Ammo_F" createVehicle getPos player;
Upon triggering the trigger, the ammo box is created but the Init trigger won't fire.
{F24558}