I received my Fenix 6 two days ago, updated it to he latest software and used it for the day. The sleep tracking worked the first night, but didn't last night. The only things I did to the watch prior to going to sleep were adjusting my bed time by 1 hour in the settings and I used flight mode during sleep. The watch did record my heart rate, respiration rate and pulse ox. Is this a bug with enabling flight mode?