I learnt some LEDs do not tolerate heat well. They work fine in cool weather and when well ventilated, but depending on where they are installed (eg open air, in down light cans, in lamps, in a display case, in a range hood, etc) when they reach their thermal operating limits they will start flashing.
If it reaches (eg) 30C in the room, a running LED in its localised environment can be running over 40C, and that is the specified operating limit for some of them. Others I have seen and usually buy are specified to 65C. I have one brand installed during winter in relatively small ceiling down light cans that worked beautifully until summer, and when we had a 35C day the internal roof space got hot and they started flashing after running for a few minutes. When the temps went back to 25C the lights were fine again. I still had the packaging and it clearly stated they were only suitable for what is essentially open air mounting. My bad at the end of the day.