schroedinbug
schroedinbug: /shroh'din-buhg/ [MIT: from the Schroedinger's Cat
thought-experiment in quantum physics] n. 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
harbored latent schroedinbugs for years. Compare heisenbug,
Bohr bug, mandelbug.