The newer ones may not, but traditionally, they dimmed when hot.
Not an issue on the playa.
Burnout became a problem with higher power ones too, but adequate heatsinking seems to have solved that.
They produce full efficacy in extreme cold, something most lamps do not do.
Desert use of heat sensitive lights is a particular problem when they are turned on before the daytime heat soak has cooled off.
Even the indestructible holophanes were cooking in the middle east if they came on too early.
You mostly see heat dimming in LEDs in cheaper plastic headlamps and flashlights.

