Interesting – I have never seen this before and I have characterised some of them with measurments every second for ~days.
I don’t think the problem is overheating – unless there is some fault in the electronics – since the lasers are dissapating fairly low power so shouldn’t heat up very much. Have you tried doing it with the intensity set to a lower value and see what happens?
Off the top of my head I imagine the most likely scenario is there is a fault the laser diode – they are fairly cheap mass-produced items, probably with far more variability than anything else in the circuitry. In that case asking for a replacement is probably your best bet – unless you fancy soldering in a new laser diode (assuming that is indeed the problem).
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