This story was news to me. One more example of how I don’t know everything I guess.
Computer chips have advanced to the point that they’re no longer reliable: they’ve become “mercurial,” as Google puts it, and may not perform their calculations in a predictable manner. Not that they were ever completely reliable. CPU errors have been around as long as CPUs themselves. They arise not only from design oversights but also from environmental conditions and from physical system failures that produce faults.