For the hacker's dictionary

A classic hacker term is phase-of-moon dependence, characterizing a bug that appears and disappears without apparent rhyme or reason. (This is distinct from the heisenbug, which disappears when you look at it too closely.) I had a bug mysteriously turn up in early January this year— and I was able to reproduce it repeatedly, on multiple machines, even using a build from early November. The exact same testing procedure on the exact same build, performed today, no longer reproduces this behavior. What’s a good name for this problem?

[Poll #670866]