Mmm
Actually, I'm making a custom spell that its supposed to be the target version of Divine Shield. I use a base spell with 0 stats as a dummy spell so it can trigger the trigger. But anyways the duration of the dummy spell is really just 5 seconds. The dummy spell is learned by a unit from an upgrade.
Try making another trigger that turns the unit vulnerable when your dummy spell is finished. Like finishes channeling. (thought that would leave you unable to fight people while you were invulnerable like phase shift). Like make the dummy last for 5 seconds.
My trigger resetting system uses two triggers, in a my own way as terminators. but I recommend making a working version of the trigger, then copying that trigger. Turn one to initially off. Now add on the first trigger at the end for action.
A: Trigger/Turn Trigger on (Invun2)
A: Trigger/Turn Trigger Off (This One)
And on the other trigger do it in the series.
A: Trigger/Turn Trigger on (Invun1)
A: Trigger/Turn Trigger off (This One)
This systems works for me as a reset and is fairly basic. On one of my maps I used a different way for super weapons which went like:
E: Unit casts a spell
C: Unit equal to Superweapon
A: Create effect at region (Target of Ability) Flame strike.
A: Wait 5 seconds
A: Turn on Trigger 2
A: Turn off this trigger
Trigger 2
e: Periodic 2 seconds
a: Turn on Trigger 1
a: Turn off this trigger
The action Trigger->Turn off is essentially the terminator. It is useful for say, stopping enemies spawning during a cinematic.
The action Trigger->Turn on is very handy too. For say if you have dialogue boxes for game modes. You can use these to activate a set of triggers needed for that mode. (Like on my Paintball Map). If you need too you can make a trigger to turn on your real spell triggers when the upgrade for the dummy is finished too.
Hope this helped and I haven't wasted my time typing it and yours reading it.