  A random-matrix theory is presented which shows that breaking time-reversal
symmetry by itself does {\em not} suppress the weak-localization correction to
the conductance of a disordered metal wire attached to a superconductor.
Suppression of weak localization requires applying a magnetic field as well as
raising the voltage, to break both time-reversal symmetry and electron-hole
degeneracy. A magnetic-field dependent contact resistance obscured this anomaly
in previous numerical simulations.
