"If while not on charge, I intentionally shut the device off and restart it properly by holding the button down ... rebooting it, without putting it on charge. It always starts up fine."

I do the same, but upon intial charge of any battery, the N800 does not consistantly power up the first time while HOLDING down the button. after it boots the first time the "problem" goes away. BTW, not all recharges do I see the "problem". I the N800 is always powered off when I charge it. (I use the spare batteries as necessary, which has not been often, I seem to get a good amount of use out of them before they show low level.)

I only posted another observation for consideration. I don't see this as a big deal for me, just a slight annoyance that should not be there.