Why does the Xiaomi Oscillation Electric Toothbrush Pro screen keep flashing in orange during charging?

When the Xiaomi Oscillation Electric Toothbrush Pro is operating and the battery is low, the charging screen will display the real-time battery level without flashing the orange indicator. A full charge takes approximately 6 hours.
To charge the toothbrush properly, please refer to the following steps:
1. Open the rubber cover of the charging port, ensure the interface is dry;
2. Plug in the charging cable, and connect it to a power source.
Note:
1. The toothbrush will stop functioning while charging. At the beginning of charging, the device will vibrate once and the screen will display “Charging in progress”;
2. Charge the toothbrush on a stable and dry surface;
3. Use a 5V/1A power adapter (sold separately) for charging.
To check the battery status, please refer to the following chart:
Toothbrush statusBattery levelScreen display
Operating20%-100%None
5%-20%Low battery level (Turning on possible)
<5%Low battery level (Turning on impossible)
Charging0-100%The battery level is displayed for the first 20 seconds after charging, and then goes out.