It's normal. Generally, when charging a rechargeable wireless mouse, turn on the power switch of the mouse (some mice do not need to turn on the power switch).
When charging, the blue indicator of the mouse lights up, and the red light at the bottom of the mouse lights up (the mouse is put out after a period of time, which is the standby state of the mouse).
After it is full (when the charger is not unplugged), some mouse is blue light off, some blue light is still on, and the bottom red light is off.
Unplug the charger, turn off the mouse switch, and charge the end.