Body Battery Issue on Garmin Connect App

Is the other data synced? Sleep score, heart rate, steps?

The watch icon in Garmin Connect looks a bit odd. It looks like an Instinct 3. Do you also have an Instinct 3? Then that might mess it up if you are switching watches back and forth.

I think e7andy nailed it - your Instinct 3 seems to be set as the Primary Wearable Device, and currently Body Battery is not among the data shared between devices with the Physio TrueUp feature (although it is just coming to select devices, in the next firmware update). It means Body Battery always comes from the PWD (Instinct 3 in your case). Unfortunately, I do not see Instinct 3 among the watches that will be updated with the BB data sharing now. You'll have to hope Instinct 3 will be equipped with this feature soon too, but for the time being, I recommend either wearing the PWD during the sleep, or setting your Epix 2 as the PWD.

Thank you so much.  I just bought an Instinct 3.  I use the Instinct 3 just for cycling and hiking.  I wear the Epix 2 for walking and sleeping.

Thanks trux.  I didn't know about primary devices.  I just made sure that the epix 2 is always my primary device.