Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding Scripting New to Scripting - Apply status on trigger

That script calls ExplodeAt() to cause an explosion-style skill to go off at its own position whenever it is triggered. This API does not specify a damage source, so it does not get associated with any item/character as an attacker.

You could indeed trigger a different skill that would set an indefinite poison status instead.