End of culture not being cast

[Salamander8]

I didn't see this brought up before (and I ran through the bug list) but I cannot get my mages to cast End of Culture as Yomi. I've had this issue before but never paid attention to it till I decided to make 100% sure I was not getting it to go off.

In my SP game as Yomi that I am finishing up, my main force has 14 Dai Onis all with enough fire to cast it without boosters or gems. All of them still have fire gems, are scripted to cast phoenix power before casting End of Culture, and all 14 are scripted to cast the spell, but none of them ever cast it. In addition to the 14 Dai Onis, I also have about 100 Kuro Onis so it's not due to lack of targets. My blessing is a mere E4, so no nature berserk effect either. I've observed the last 5 battles this group has been in after deciding to try scripting the spell with all my Dai Onis instead of just 1 and they have never cast the spell. Has anyone else had this problem?

[Micah]

Gem conservation mechanic kicking in perhaps? Have you fought anything that wasn't just scattered PD with your huge oni army?

[Salamander8]

Oddly enough, one of my smaller forces with 4 Dai Onis and some of the lesser ones did cast it without a hitch. It was a siege as well, so it seems that conservation is the reason after all.