The battery level of my HUAWEI tablet remains at 99% when charging, and only reaches 100% after disconnecting and re-connecting the charger

Charging will automatically stop when the tablet is powered on for a long time. If your tablet stays on while it is plugged in, energy will be consumed and the battery level may fall to 99%. Charging will not resume in this case, in order to protect the battery, and thus the battery level will remain at 99%.

Once the charger is reconnected, the battery will resume charging and the battery level will display as 100%.