An executable from a nightly build kept crashing and I got tasked with fixing it. I was a novice back then and spent most of the day trying to figure out what was happening, and when looking at the disassembly I saw it was crashing at a 'hlt' instruction, which shouldn't have been there.
Next day, after another nightly build, no more crashes. I did a binary diff between the crashing version and the new one, it was a single bit. A bit flip on the build server.
Next day, after another nightly build, no more crashes. I did a binary diff between the crashing version and the new one, it was a single bit. A bit flip on the build server.