Versions
Minecraft 1.18.2
Forge: 40.0.42
Hex: Commit 620b751
Paucal: Commit 92990a8

Casting the spell via impetus also does not deal damage to yourself if you were the one responsible for the activation.
Haven't tested with other players, or in multiplayer.

psi works the same way, actually. i'm gonna defer to petra on the intentionality or otherwise of this.

Works as intended