Same iPhone detected as new device

[ztm]

Hi there,
I use the Facebook log in and sometimes I find my user logged out of the iPhone app, even if I did not disconnected (say once every 10-12 days).

I tap "Log in with Facebook" and all my downloaded music is gone.

I go to the connected devices list on the web and I see the iPhone appears as a new device, even if it's clearly the same one and I don't have more devices.

Is there any way to solve this?
I have Spotify 7.9.0 and iOS 10.2.1.

Thanks