THC doesent work when G code is running

while doing the first tests on my machine I noticed that THC doesnt work when the machine is running G code
I looked around and did some tests and it does work and move the z axis when I start a manual cut with f9 and jog with the arrow keys

QtplasmaC is getting arc voltage and arc ok signals 
the G code im testing is the metric wrench and things from the conversational panel
the THC enabled light turns on but not the active light
it looks like the machine is getting up to the feed speed 

how should i troubleshoot this and am I missing something obvious?