Minecraft wiki entry for Potion, associated text: Corrupting an extended or enhanced potion usually results in a corrupted potion with the same modifier applied, if it is supported by the corrupted effect. Of the four corrupted potions, Harming is the only one that cannot be extended, and also the only one that can be enhanced. In Bedrock Edition, the corruption of Healing II and Poison II potions results in a Potion of Harming I.