Did you ever see the "Plug" instead of the Lightning bolt? That is the Full symbol.
Did you check the Batter wire plug (under the door) to confirm it is fully seated in the socket?
Some "bounce" (1 bars worth) is normal, just like the fuel gauge in a car, various conditions change the readings slightly, moment to moment.
My PEz is now 5 months old, and I see this occasionally. Just another reason to not wait another week to recharge