I have not had any issues with my Edelux until my last brevet, which had considerable amounts of washboard gravel roads.
As night approached, I reached down to turn on my lamp and BZZZRT! I got a pretty hefty shock to the fingers when I touched the lamp housing. It happened a second time when I groggily forgot about the first time, and reached down to adjust the lamp position.
It only happens if I'm at speed, or have just recently stopped after a riding for a while. When cleaning things up a bit yesterday, I gave the wheel a spin with my fingers on the lamp housing and didn't get juiced (at least not that I noticed.)

I did notice that my standlight is barely functioning right now, and that regardless of the switch position the light was staying on. Does it sound like I rattled the internals loose somehow without dislodging the LED (since the beam pattern is still fine?) Is the high-powered zap the standlight cap discharging when I touch the housing?

I doubt the capacitor discharge could give you the sensation, at least for dry hands. My bet is that the capacitor is some stock computer supercap charged to 5-6V. After all, you don't get shocked by phone lines with 48V. Otherwise, if your hand can get the sensation, then also transistors inside the lamp can get damaged. The standlight situation may be an aftereffect rather than the reason.

Significant voltages can be generated if the dynamo is subjected to a load and the load is disconnected. This could be done many times per second by the electronics, without visible effects as far as illumination is concerned. Normally, there is a protection across the dynamo protecting against the voltage spikes. Maybe that protection got disconnected. As a remedy external to the dynamo and the lamp, you might connect the dynamo terminals with either back to back Zener diodes, say 15-20V/3-5W each, or a snubber out of a 100nF capacitor in series with a 100 ohm resistor.

Note though that I have no personal experience with Edelux and otherwise obviously cannot guarantee that the suggested remedy will work.

I believe the Edelux has a relatively long warranty so get hold of Peter White Cycles who I believe are the primary USA importer and see if he can help you. No point in getting shocked and having a poor working standlight. I would consider the latter defect a safety issue.