It was my original mod that Quinlivan documented.
It is rather a copoff for audi in the RS4 tbh, as still needs key in & turned, but not started, I only installed as had it left from my S4 B6 I didnt fit, so tested on A3.
It will not trigger starter again as once car is started, it disables that side of things even on the key aswell, it connects to the starting circuit, just a simple PTT button that signals a relay to starter.
Bez the RS4 never turned the engine of aswell afaik mate, so how did you wire yours in if I may ask, unless you added some relays etc to reverse the wiring when car started, to kill the power, but then again the key would still be in the ignition switched position.