Source : Free On-Line Dictionary of Computing

schroedinbug
     
         /shroh'din-buhg/ ({MIT}, from the
        Schroedinger's Cat thought-experiment in quantum physics) A
        design or implementation {bug} in a program that doesn't
        manifest until someone reading source or using the program in
        an unusual way notices that it never should have worked, at
        which point the program promptly stops working for everybody
        until fixed.  Though (like {bit rot}) this sounds impossible,
        it happens; some programs have harboured latent schroedinbugs
        for years.
     
        Compare {heisenbug}, {Bohr bug}, {mandelbug}.
     
        [{Jargon File}]
     
        (1995-02-28)