Not sure why that would happen, but you can also claim the device via Web IDE (or CLI if installed).
You just need to find out the device ID and then in Web IDE (make sure to be logged in with to the same account in Web IDE and your mobile app)
Hit ADD NEW DEVICE and enter your device ID (while the device is breathing cyan).
After that your device should appear in the list of available devices and by clicking on the device name you can rename it to what you want.
After that you should also see the device in console.particle.io/devices and your mobile app.