I don’t have any data beyond my own entryway, and I can’t find much information out there. I have had several PAR20 LED bulbs go bad well before the promised years of life.
My woodburning stove is in this room, and the room can get pretty warm. There is a thermometer in the room, so I know at times it gets up to maybe 80 degrees Farenheit. Probably warmer in the ceiling and enclosed bulb spaces. However, it doesn’t seem to be the bulbs closest to the stove that go bad more often.
My theory is that the LED bulbs don’t take the extra heat well. The halogens I used to use lasted just as long as these LEDs have, if not longer. I’ve started writing the install date in sharpie on each bulb as I put it in.