Sorry for the trouble.
This is a known issue in v2.20.40.90 and we’ve addressed the root cause, planning to roll-in the fix in next update. Before receiving the fix, please follow the instructions below to get a work around for one of these two error cases.
Cases1: charging battery level up to 70%
1. Unplug your USB changing cable to STOP the error message if it’s continuously pupping up
2. Get into Settings > Battery
3. Click Menu on upper right, and select ‘Set Battery charging ready reminder’
4. Select ‘Never’
Case2: battery level less than 15% or 5%
Once your battery level down to 15% or 5%, this error will happen again. There’s no work around for this case, but you still can successfully continue your usage after dismissing the error message. (this error message will appear only once in this case)
Sorry again for the inconvenience.