I did the modification to disable the Auto start-stop.
It works well, no problem there.

The only things I find strange, is the orage LED on the button. Sometimes, it will blink at a very fast rate but most of the time it is simply ON.

Is there someone that have seen the same behavior?
My information display always show 'deactivated by switch' or something similar, whatever the condition of the LED.

 

Nobody with the modification has the flashing LED?

 

I didn't perform the mod you referred to but did have Livernois permanently disable the auto start/stop with the tune they provided. No flashing light on the LED (no light at all is lit on the switch) and no notification in the center console informing that it's disabled.

Probably not helpful for what you're asking but thought I'd share.