Does anyone know what causes these little divots at the start/stop point of the plasma arc? The area of concern is at the bottom of the O in the photo. The most obvious cause to me was a lead-in/out that was too small, but increasing those seem to have no effect; they still show up even when moving the pierce point well away from that area. The piece in this photo was done with new consumables so I don't think that has anything to do with it either.

I think my setup has always done this, but it is more noticeable now that I am doing more detailed work with 1/8" steel. About the only other thing I can think of is to try placing the start/stop on an inside curve to see if that makes a difference, but obviously that wouldn't work on round or oval cuts. Any other ideas?

My setup:
Precision Plasma 4x4 LD gantry
Hypertherm 45
BladeRunner Dragon-Cut 4-300 kit with DTHCII
Mach3 and SheetCAM