Raise your pierce height Say 0.1 or maybe a bit more
Turn Up your amperage, no reason to do 1/4" at anything less than 40-45A
Up you speed quite a bit that is way too slow. I do 1/4" at 30-35 ipm and 45 A
So making progress, tweaking variables. I am finally cutting all the way through the 1/4" mild steel. But no variables I have tweaked so far seem to affect the fact I am not quite getting the full 360-degree to cut all way through. Looks like dross/slag is filling back in that last part of the arc. I am thinking:
I’m very new to this, cut my first piece today with it after uploading from Fusion 360. So take my suggestion lightly but I would try increasing the off delay, I had mine set to what yours is on 20 gauge stuff and had similar results of it not completing the cut. I increased it to .5 I believe and it took care of it on the thin stuff.