IIRC, v3.043.022 is the version I had that problem with. However, it was only an issue when the Z axis was set for lower velocity/acceleration than the other axes, and only when transitioning from a 2-axis arc move to a three-axis move. Mach3 would ignore the Z axis acceleration, and command it to accelerate at the rate of the other two axes, which, of course Z could not do. I've been told it was fixed quite some time ago.
Have you tried running with a more recent version of Mach3? That one is quite old.
Regards,
Ray L.