Since 3 days ago my Vivoactive 4s' battery drains from 100% to zero in about 9 hours. This also happens during the night, when the watch is fully idle in DND mode. Fully charged before bedtime, and was 6% this morning when I woke up.
Nothing has changed in the settings, and the watch battery lasted for days before. Tried device reset (without deleting data), this did not help.
The drop in battery life was sudden and drastic, and does not seem like a normal, gradual weakening of the battery. The watch is a little over 1 year old. SW version 7.80.
Custom watch face turned off, no change. Pulse Ox not in use. No activities recorded in this period.
What could cause this?