Oh, dear! Thanks for reaching out! We do want to make sure your phone is working at its best! We'd be happy to dig deeper into the troubleshooting, and get your device working properly! Please, send us a Private Note, to get started!
I have exactly the same problem with the same phone. The fingerprint unlock feature works after the phone has been unlocked with a PIN, then manually locked. However, if I let the phone sit for any length of time, it will no longer unlock with the fingerprint reader. If you get a solution, please post it so I can fix mine as well!