Interesting... could be that the surge protector strip has a constant fault current of 10 mA or so and power filter caps in the oven or something like that add enough current to trip the RCD. It'd be interesting to plug that power strip into an appliance tester or clamp an amp meter to its earth wire to see how much leakage it has. Remember, 30 mA RCDs are supposed to trip anywhere between 15 and 30 mA!
