Opponent was able to use the pendulum effect of Nervedo to negate my own effect activating in response to my Power Patron Monster’s effect. Screenshot below, I can also dig up the replay if needed.
Im not seeing anything wrong here. Nervedo simply states that you can negate a monster effected your opponent activates in response to A “Power Patron” or “Artmage” monster effect, not specifically YOUR “Power Patron” or “Artmage” monster effect.