Not sure what happened, but I got charged twice for Order #2116095.
Does this FAQ help out at all?
This is a pretty common misconception between authorizations (which fall off automatically) and an actual charge.
It sucks, because the authorizations often tie up funds until the bank releases them, but most of the time, people aren't actually double-charged.
That could be it. I do know I had to authenticate twice, however (type in information twice), before it picked up.