That didn't work (AI)

[Finalgenesis]

The AI do place a high priority in avoid hitting your troops with AoE.

I suspect Astral geyser being a special case since its AoE is "invisible" as spell description only shows AoE 1, AI think of it as having 1 AoE only, thus no FF issue and can be safely used, it doesn't enter their calculation that its actually closer to 9 AoE...

Maybe switch to stellar cascade? Half the fatigue, works amazingly well on SCs of all kind, also works on troops, always hits with decent AoE. Their AoE is actually recognized so they should switch to say paralyze or something if someone gets in among your troops.

[krpeters]

My troops eat AI "SC"s easily enough; it's his horde of light infantry and archers I'm trying to kill. Fatigue might slow them down, but they're not high-encumberance troops that are really going to get ruined by it.