That's exactly what's happening. How to modify it to be an AC over-voltage crowbar for both polarity?
Your reasoning is faulty. You're producing a flat out short-circuit which will cause massive currents to flow through the triac. The voltage across the AC may be 0~1V, but by god the AC will shove as much current as it can through the resistance or diode drop to try and get the voltage back up to where it wants to be, or until something gives.A TVS / zener only limits the voltage over the breakdown, which is too much heat. The triac clamps about anything over 1V which in my case collapses the power and results in no heat.