What’s causing this slag on -move on x axis

Usually, cutting to slow or lack of air pressure.

Overall it looks like you aren’t blowing the molten material out correctly, or the odd material type you mentioned is really bubbly when it oxidizes.  You really shouldn’t get that kind of dross on either the part or the sheet.

Two thoughts on things to check:

1.  Ive seen this in testing when the torch to material distance becomes too large.

2.  That material looks too thick for fine cut.  Try the same cut with 45amp nozzle using 45amp material speed settings.  Eventually if it works you'll have to re post to account for the different kerf width.  I was like you thinking that “fine cut” = greater precision.  It’s true but only in thin sheet metal.  For anything else, while there may be cut settings in the hypertherm manual, you should steer clear.  I’ve had better success with 45amp consumables and settings in materials similar to what you show.  The kerf width of the arc in conjunction with the thickness doesn’t allow the molten material any place to go.  And thus it can’t blow it away correctly.