Hi Nate -
I used to get calibration messages when I owned the original 1DX as well. So far it hasn't happened with my new 1DX II. However when I did the calibration, the message always went away. So I'm not sure what might be happening in your case. The only issue I can see would be if the charger does not let you recharge the battery without doing the calibration. That is annoying because the calibration can take quite a while. If you can recharge without calibrating, then I'd just ignore the message.