@kwarth I strongly don't agree with the manufacture on the measurement. As I said, this has nothing to do with excessive power in mW.
@Shike, Head Injury and Yoga Flame: It's worth confirming this isn't a freak problem, but Jason from Schiit has already said it's normal. And single ended amps are pretty simple. If there was something wrong with the amp it's rather unlikely it would affect both channels and still sound OK while playing.
This should be easy enough for another Asgard owner with similar headphones (they don't have to be AKGs) to confirm--at least if they're willing to risk damage to their headphones by turning it off with the headphones plugged in.
There's an interesting irony here. There are some amps, including the AMB Mini3, that can allegedly be damaged by unplugging the headphones with the amp powered on. But with the Asgard things are reversed. You're supposed to unplug the headphones with the amp on. Obviously neither situation is ideal if getting it wrong can cause damage. And it's a lot of wear and tear on the headphone jack unless you just leave the amp on 24/7.
Sooner or later, it's likely you'll get it wrong, the power will go out, or whatever. And it might just take once to damage your headphones.
An interesting idea would be to direct one or more headphone manufactures to this thread (or at least the video) and get their input on potential damage to the headphone drivers.