Hmm. I killed a GB diode the other day - had been running it at 250ma with a series resistor on a Dorcy. Wanted to see briefly what the current would be without my 1 Ohm resistor - goes up to 275-280, which should be okay for a little while, especially since the diode was still in a heatsink. The diode has a protection capacitor and reverse polarity diode.
At first I figured it was spikes that got past the capacitor or static discharge.
But the more I think about it, I bet there's an output capacitor on the Dorcy driver that charges up when there's no load.
So, loose connections to a boost circuit = LED