mangos/mangos — comment on commit 6d8ef98bb0d75aca141cc8d244ab886bae7aa345
File: src/game/SpellEffects.cpp line 3604
By rsa:

this is completely wrong approach.
targetA = "source" target
targetB = "dest" target.
effect coming from source target to destination target. if source NULL - effect coming from nothing, but not from destination.