Sprint Wi Fi calling broken again after recent update

Sprint Wi Fi calling stopped working on my iphone 7 after the 11.2 update. Both Apple and Sprint looked into this problem and Sprint released a carrier update that seemed to correct the problem. After updating the phone to iOS 11.2.1 the problem has returned in part. When the phone sleeps overnight it loses the setting. If I toggle off Wi Fi calling and toggle it back on, the phone will reconnect and remain connected unless it goes to sleep for a long period of time. There is still something fundamentally wrong with the function.