Leon, you are on your game. The lights in question are failing because of the associated electronics as well as plain poor design. The associated voltage steppers that go with the 12 volt system are for the most part just junk, and inside the box they look like a ballast for a florescent fixture. No complicated electronics or circuit boards, heat sinks or anything else. So the 12V systems fail at the transformer/voltage reducer according to the lighting engineer I met.
The larger bulbs are failing NOT from electronic failure, not from any voltage problems, or anything of that nature. Bright, room lighting LEDs are not flashlight bulbs or low voltage stuff that you put in your china cabinet. They generate a fair amount of heat, and they must be put in a fixture that dissipates heat or has a proper heat sink. These bulbs however are being used in living room lamps, track lighting, room lighting, etc. and those fixtures probably don't allow the heat to disperse. Certainly, the big box stores provide no warnings on proper usage, and that is where the problem starts. Unless they are extremely low lumen, those types of bulbs should not be put into fixtures designed for incandescent bulbs. The additional problems with the bulbs are that they are usually bigger than the incandescent bulbs, and they block air flow even more.
Until about a year ago when I put in my first set of LEDs and was educated by my electrician, I thought I could cover up the ceiling cans for better attic efficiency. I was warned then about the heat, but I thought it was only on dedicated fixtures (in this case kitchen ceiling recessed cans). No insulation on or within 2" of the cans.
Adding to the problem is the lack of quality that many of the LEDs exhibit. The overwhelming bulk are made in China, and that has led to all kinds of quality variances. Most large companies make bulbs there, but many are certified as 900X factory manufacturers, so that helps with manufacturing, but then it doesn't do anything for a poor design. Crap is still crap, it is just well made crap.
According to the lighting engineer, by the time the recalls are over, there should be about million bulbs being recalled voluntarily or involuntarily, and at this point he said the count is at about a half million. I can see that. He was pulling out almost 3000 of these types of bulbs on a shopping center that were put in by a competitor. His competitor simply changed the bulbs... not enough air flow around the bulb (and according to him a very crappy bulb to begin with) and the were literally melting parts of the bulb and fixtures.
While on topic, he also affirmed what I had read about manufacturer's changing their claims of LEDs lasting an average of 50,000 service hours. One of the trade publications I had come across said that a more reasonable figure for quality LEDs should be pegged at 25K, not
50K of service hours. The engineer said their newest packaging is coming in with that on the boxes, so something else to think about.
While the service hours won't affect any of us, he does malls, parking lots, parks, warehouses, factories, car dealerships, etc., so he is always keen on all aspects of lighting from a lamp to a factory floor. It was good for me to get it all straight from an expert.
Robert