I have, and most bizarrely! I'll have to dig through the archives to find a pic but 2-3 years ago a mate had a new problem in their (old) house that they'd been in for years and after some testing I'd narrowed it down to one cable that I could see both ends of, about 5m long and in visually perfect condition, not disturbed since installation many years earlier. After some headscratching and guestimation I peeled open a section of sheath to discover that there was a manufacturing break in the conductor, clearly a good couple of mm. There must have been enough of a bend or whatever at that point to have made the ends make contact and 'work' for the twenty odd years it had, but there was no signs of arcing etc. Most bizarre.