A close-up of the intersection region showing (from the red and green crosses) that stable vapor is on the left, stable liquid on the right.

As noted before, the white curves of constant
µ3 are actually separate graphical elements (tapes) that lie above the blue and yellow phase surfaces. The slight gap (which was necessary for graphical purposes) causes the curves not to intersect at precisely the same spatial point as the phase surfaces. The error is a visual artifact only.
Iowa State University