that is normal, not a defect.
Switching Battery Power Supply
Tube series support double power supply system: Built-in li-ion battery pack and
replaceable 18500 battery, also support USB port charging.
⚫If there are two batteries in Tube, two battery icons are displayed in the status bar
( the replaceable battery on the left while built-in battery on the right ). The battery
from which the device is powered is displayed in green, and inactive is in gray.
⚫If there is no replaceable battery in the device, only one green icon of the built-in
battery is displayed in the status bar.
⚫When both batteries is fully charged, the device will select replaceable battery as
power source. If the power of the replaceable battery is in low level, the device will
switch to built-in battery as power supply.
⚫When charging the device using the USB port (9), it will switch to external USB power
supply, meanwhile charging the built-in battery. And a lighting shaped icon will appear
inside the icon of built-in battery.
⚫It is possible to replace the replaceable battery when the device is power on ( the
device will switch its power supply to built-in battery ).
7. External Power Supply
Tube series support external power supply, such as mobile Power Bank (5V).
⚫Connect the external power supply to the USB port (9) on Tube.
⚫The device will switch to external power supply, meanwhile charge the built-in battery
pack.
⚫When the external power supply is turned off, the device will switch to replaceable
18500 battery first without turning off. If there is no replaceable 18500 battery or low
power level, the device will switch to the built-in battery pack as power supply.