Apple watch series have faced some issues with the update in the past and something similar also happened a few months back with the new update for Apple Watch SE and Series 5, where the users reported battery drainage. The problem was very specific to the Battery Saving power reserve mode in both models. At the early stage, Apple provided free repairs to the owners but now the company has rolled out yet another update for Series 5 and Watch SE which fixes the issue automatically.
The new update is watchOS 7.3.1 and the update log states that “watchOS 7.3.1 addresses an issue that prevented some Apple Watch Series 5 and Apple Watch SE devices from charging after entering Power Reserve“”. In case you have the same device and were facing an exactly similar issue then you simply have to open the Watch app and go to the General options. Once there, select the Software Update option and download the new update. Once the update is installed, the issue will automatically be resolved.
However, make sure that while updating the watch, the battery percentage is more than 50% or the watch should be kept on charging. To check if the issue is there in your device, place it on the charger and wait for at least half an hour. If the device fails to begin charging, it means that the device is affected. Although the company has already discontinued the Apple Watch Series 5, they will continue to support and provide updates for the same