If G64 is selected then it will run in that mode unless the code changes it. In other words if code has G61 in it it will change to exact stop mode and it will not get set back until a G64 is seen in code or you restart Mach. So all code should really have a preamble setting the correct modes for that code, not just G61/G64 but others such as G90/G91, G90.1/G91.1 etc etc
Hood