A Solution - Factory Seating Issue?
I don't see how software updates or any other waving of hands or other magic tricks (plug it in first to the computer USB, wait five minutes, genuflect, go to AC power plug in Kitchen 'cause kitchen outlets are more powerful than other outlets, cough, plug in AC adaptor twice, 5 seconds apart, click heels three times) has anything to do with what is obviously a herky-jerky plug.
The AC adaptor that came with my iPhone also displayed 50% reliability when charging. Very annoying. I bent the prongs. I tried another outlet. Same unreliable behavior. I then slid off the whole corner where the two prongs are and then replaced it back in the little brick. Just for good measure, I did it 2-3 times.
All is well.
Granted, I should not have had to have done this in the first place, but it sure beats going to the store to replace it with another AC brick that will likely do the same thing. Methinks it was a seating issue at the factory - what-ev-ah.