Connect to BT on nd5xs2

I disabled this input a year ago, but to my surprise one of my guests somehow connected to it.
I tried to connect using my phone, but failed. The settings show that the input remains disabled.
Who can explain the miracle? This guest did not touch neither the streamer nor my phone where the naim app.

Are you sure they connected via BT? Did they have an apple device? In which case it would be though AirPlay