Watch Series2 suddenly dies, 4 times in 4 days

Has this happened to anyone else with a series 2 watch?

1. The watch shuts off, and will not respond to simultaneous button and crown press for more than 10 seconds. No impact to the watch, no swimming or showering before the watch goes completely dark.

2. Only putting the watch on the charger for about 5 minutes will the watch turn back on.

3. Plenty of power in the watch when this happens. And when the watch comes back after 5 minutes on the charger, the battery charge level is at 60~70%.

4. I called Apple Support. Someone ran remote diagnosis. All stats on battery are great. I have had the watch for about 100 days. The battery has only gone through 38 cycles.

5. WatchOS 3.1.3.

What gives? Thank you.