[Jim Dawson]

I replaced the steppers with servos and it still stops during milling process at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock. Plus the circles are still not round.

Rather than run a Bore operation, make the same cut with a Contour operation with the Ramp check box checked on the Linking tab. Around a 2 degree ramp. Should give you about the same tool path, but the G code is much different. Maybe your controller will like that better.