will one day function faultily at the wrong place and time.
What we non-technopersons, bruised by experience and unhampered by blind faith in statistics and commonsense, call "Murphy's law". n'est-ce pas, named for an engineer called Murphy, somewhere in the USA, who was found to have an uncanny ability to do something wrongly if there was a way of doing it wrongly, no matter how difficult it was to do it wrongly.
Now simply stated as "Anything that can go wrong will go wrong" to which many of us add "when you least expect it", although that bit is uncorroborated by hard evidence, unlike the law itself.
"Function faultily at the wrong time and place" is very good and succinct, but I prefer the wider scope of the original Law.