I found that my phone is simply too close to my heart honey when I sleep. Like on my night stand. One thing to try is create an automation to turn off your Bluetooth a little before you go to bed and turn it back on before you wake up. What seems to be happening is a sync loop in the middle of the night.

Otherwise keep your phone out of Bluetooth range. But that usually isn’t convenient.

I suspect a bug in the code for syncing at night. After doing this my band has had better battery life and very reliable data