[Kiwi]

I had the same problem with my Machine Centre with a Fagor 8055 controller.
The fix is to put G51 E0.0001 at the beginning of the program.
G51 is the Look-Ahead mode which enables the CNC to look ahead up to 50 lines, analyze the tool path and calculate the max feedrate with an max error of 0.0001mm.
Don't know if Mach has the equivalant feature.