Quote Originally Posted by richie00boy View Post
Could it be an issue with my drive controller?
Chances are it won't be a drive problem. Looking at the holes offsets and the fact they offset consistently it's More likely to be either a lose coupler slipping or you have acceleration set to high in Mach causing it to jump the odd step on direction changes.

Post the tap files and will check for you. Will combine into one G-code file and then you'll see on the screen if holes are offset or whether the machines causing the problem.