Such flashing can also be caused by damage to the diode itself or the connections.
The diode and the parts of the housing heat up, stresses cause a break in the circuit in the damaged place, e.g. crack, defective solder, it cools down, the circuit closes again and the cycle repeats itself.
I have encountered this type of damage many times, even in brand LED luminaires.
Often the cause is a design flaw - the cooling capacity is too low. Sometimes you can see damage - if it is a luminaire with many diodes connected in series (the power supply is a current source, with a certain voltage range on the load, which is known by the fact that the power supply has the current and voltage range on the load), you can see that one diode is damaged - it has a different color or there is a different color at some point. If the power supply has a large voltage range on the load, you can reduce the power of the luminaire by removing and bridging some of the diodes, which will reduce the amount of light but also the thermal power, which will lower the temperature and extend the life of the luminaire.
There are a series of luminaires with different powers, which have the same power supply, Philips 50W and 70W led luminaires (I do not remember the type, they are from the same series) have the same power supply, and they differ in the number of diodes in series, modules with diodes in the whole series are the same, there are more modules connected in series in the luminaires of higher power. In these luminaires there was a problem with the bridges between the modules - they were of some very difficult solder alloy, so that even in the factory they had a problem soldering it, when I replaced all the bridges for copper.