I only bought one mouse, so why do two mouse names appear during authorization?

I only bought one mouse, so why do two mouse names appear during authorization?

Don't worry — this is normal. It doesn't mean you have an extra mouse or that anything is broken.
The two entries you see are actually two connections of "the same mouse": one connected via Bluetooth, and the other connected via the USB receiver (Dongle) at the same time.
Just press the signal-source switch button on the bottom of the mouse to switch to the one you actually want to use (e.g., Dongle), then select the matching authorization.