Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding Troubleshooting No way to set item OffStage in Editor?

You should be able to, set the bool to 0:
SetOnStage(ITEMGUID_BLD_Humans_Prison_Grating_Door_A_000_b5e89243-b8ea-4873-99a5-371c713e32e2,0);