because your problem is with the final curve, it leads me to believe its something to do with the curve degree

as a default, maya would use 3 cubic (if you open up the options for the CV curve tool ull see what i mean)
3 cubic means that you draw 3 points, and the "curve" wont form until your next (4th point)
you might want to try using 1 linear which wont give you any curviness at all
this could be your problem although i have never tried it and thought it was only to do with drawing of curves, but its alli can come up with