Meta Quest 3 Elite Strap Extended Battery Failure
The headset does not recognize the fully-charged extended battery on the Elite Strap. Unplugging the battery and plugging it back in does make it show up for a very brief period, but then it disappears and the headset's internal battery continues to discharge.
This headset and the battery was plugged in for about six hours, during which the Elite Strap's battery fully charged, but the headset's internal battery did not charge at all.
Meta Support has advised me to flip the USB-C cable around. 🙄