Fair enough but they don't get hot, nearly any glue would work, Being plastic, I would use CA(superglue). After failure I like to do a postmortem teardown, it

Fair enough but they don't get hot, nearly any glue would work, Being plastic, I would use CA(superglue). After failure I like to do a postmortem teardown, it has never been the LED proper, usually it is the capacitor in a capacitance power supply, otherwise the controller IC.