I had a similar problem when using parallel port on windows 10 and Mach3, while running 3d g-codes (X,Y and Z simultaneously). I swapped to a ethernet smoothstepper (ESS ) control board and have not any issues since!

Was the first carving program also 3D or was it 2D? Becuase 2D worked fine for me, but not XYX movements at the same time.