I don't know what the cause of this is, but whenever I use a persistent effect to start an attack, the attack refuses to fire. If I use it without the persistent, it still works. This does not happen with almost purely copied (Firebat clone) or blizzard attacks, which means I have no idea what I am doing wrong.
If you use a persistent effect to create two attacks on a unit, for example if you want a unit to shoot two projectiles instead of one, here are some guidelines to follow:
In this example, the Marauder will launch two projectiles instead of just one.
Create a Persistent effect.
Name it to "Punisher Grenade Double Attack" (Or whatever you want )
In the field "Period count", set 1. (This means how many extra missiles will be launched after the first one.)
In the field "Period duration", set 0.25 seconds. (This means how long the delay is between the missiles.)
In the field "Location", set "Target unit". (This will make the missiles be launched at units.)
In the field "Time Scale Source", set "Caster". (I am not 100% sure what this value does)
In the field "Period effects", select Marauder - Punisher Grenades (Launch Missile).
Then go to the weapon "Marauder - Punisher Grenades" in the Weapon Tab. Find the field "Effect" and add your newly created persistent effect there.
This means that whenever the Marauder attacks something, its persistent effect checks how many missiles it will launch. Since we set period count to 1, it will launch one extra missile. The delay between each missile is 0.25 seconds. And of course, the missiles are launched because we added that effect in the "Period effects" - field. If we add something else there, other stuff will happen.
@Kabelkorven: Go "Time Scale Source" defines which unit is responsible for altering the periodic values and every other time-realted value for the effect. So in this case if the Marauders has is time scale altered somehow it will affect the speed it launches the second missile.