Firstly, I have to say this is more an annoyance / bug rather than something being broken or not working.
In my Action Center the Bluetooth Square is blue (turned on) saying Not Connected.
Here's the thing though - My PC doesn't have any Bluetooth capable hardware components. It's not a laptop, the motherboard doesn't have this functionality, and no devices connected to it have Bluetooth features either.
I've researched online and most suggestions revolve around
- turning Bluetooth off - I can't do as there is no on/off switch in the settings
- removing the Bluetooth device from device manager - I also can't do, as there isn't a Bluetooth device listed there.
- going into network settings and disabling it there - I can't disable it from network settings as there is no network adapter to do so.
- Unpin Bluetooth tile from Quick Actions - It isn't in the quick actions list to add/remove