Headline's a bit misleading. They've never permanently lost a bag, and well done to them for that, but they've certainly lost them for periods of time. Just eventually found them.
Was flying into Narita once and I had checked luggage in part because I was carrying an award for a Japanese customer. I was sort of given a "we'll get back to you sooner or later." At which point I explained the situation to a supervisor I think and was much fluttering around and got the bag the next day.