My Homemade plasma CNC

Remember a plasma cutter is a blunt axe, not a surgical scalpel.
Ask yourself is the cut quality adequate for welding and fabrication? It will never be like an accurately machined part.
The plasma primer has some info about cut heights and angularity
linuxcnc.org/docs/stable/html/plasma/pla...mer.html#_cnc_plasma
 

For the edges of the parts, this is not a big problem for me, but the main issue is with the holes—they are oval instead of round.
I have already read this page and understand the height vs. angle relationship, but why does this only happen in the Y direction in my case?
On X direction the cuts are perfectly straight.

Is the Y properly calibrated?

What hole processing does Pronest have?
What diameter hole are you cutting?
What material and thickness?

Its suggested to slow cut velocity to about 60% for holes.

Is the Y properly calibrated? Yes

What hole processing does Pronest have? The defaut processing, into Pronest, I change the material and that's it
What diameter hole are you cutting? The last cuts were with 62mm hole diameter
What material and thickness? Same, the last cut were with midl steel, 15mm thick.

I wil try next time  reducing feed-rate to 60% and see. But I think it will be the same because i've got this issue also with straigt cuts