Version: 3.1.1
Astral Sorcery ritual Discidia (damages hostile mobs) does not damage Carminite Ghastlings. Im experiencing this issue in the overworld, have not tried duplicating in Twilight Forest.

This appears to be a bug with Astral Sorcery and their method of determining whether an Entity is hostile. Presently, no ghast variant is considered hostile.

I have submitted a report to them here HellFirePvP/AstralSorcery#1141

@sk2048 This is weird, as I have used the astral discidia ritual in previous versions of Sevtech and it worked then. (8 months ago I believe was my prior play through)

That would make sense as they changed the criteria 7 months ago from something that would work on ghasts to something that looks for things that inherit from EntityMob which Ghasts do not, instead implementing IMob directly. Carminite Ghastlings inherit from Ghasts and so are also not valid targets.

It was previously any EntityLivingBase except the player and some specific things from Astral. I'm guessing this version was capable of harming passive mobs too, and that the current state of affairs is an oversight due to the Ghasts slightly weird inheritance.