I just tried swapping the regulator out with another one, didnt seem to change anything.
Also, from what I can tell, The parts I was cutting messed up in the same spot, right after the last pierce. Seems like the purging air had just shut off right as the torch finished zeroing for the last pierce and restarted, it pierced the sheet, and didnt fully cut for the first .375"-.500" of the cut before finishing normally.
Maybe something is gummy and sluggish to respond? Just not sure what else there is besides the reg and the solenoid valve.