Hi,
to my knowledge development on Mach3 ceased five years ago, so no it has not been re-written.
The latest build is 066 however many believe it to be buggy and prefer 062.
I rather suspect that there is some setting you are overlooking rather than a change in Mach3. As to what setting, I don't know, I upgraded to Mach4 about 18 months
ago.
Craig