This is my second Vivoactive 3 watch that I received as a replacement for the original one. The original watch could go for 5-6 days on one charge if I did not use GPS much, then after about 2 years the battery started to fail. Garmin sent me a refurbished watch as a replacement. The first replacement failed badly, and the second one, which I have now, was performing pretty well. It could not give me the same 5-6 days, but I had to charge it maybe once every three days. Up until now. I have no idea what happened, I have this watch for about 6 months, but suddenly it started draining the battery so fast that I have to charge it every day. I checked it on the days when I had GPS activities and when I did not have any, regardless I lose 50-60% of the charge within 15-16 hours.
When I plug the watch to my laptop, and I always charge from the laptop, I see a lot of other weird things. Once it showed me a triangle on the black screen, and this triangle would not go away no matter what buttons I pressed. I finally had to reboot the watch, and even the reboot did not work from the first attempt. Another time the watch showed "verifying connect iq apps" for an hour, and I finally had to reboot the watch again. After the reboot it lost all my daily activity.
I do not have any custom watch faces and have never downloaded anything except of automatic system updates. I wonder if one of the system updates is an issue.