Shattered Kingdoms

Alright, I thought I'd ask here.
I'm quite confused about the way the spell works on NPCs.

My question is, what affects it and why does it seemingly randomly not do anything?

This example actually happened in sequence, the spell being spammed one after another (obviously everything else edited out)




I did not fail any of the spells, but one just didn't do anything whatsoever.
I can find logs where its quite opposite, where It does nothing three times out of four. >_<


Thanks
TBM

Edit: Edited out the NPC name

The NPC made its saving throw. On energy drain, for some reason, the target gets a message on failure instead of the caster.

Ah, that would explain it.
Thanks, I figured it would be something like that.