Have you noticed any issues at the same time? Yesterday my music stopped in the middle of my run as I was skipping to the next song via my Bose Soundsports. I paused the run and saved for later, then restarted my watch, then continued normally after having to re-pair the Soundsports. Looking at Garmin Connect later I noticed my Connect IQ Power from my HRM-Tri cut out around the same time and never restarted.
Today I ran and after finishing found I had no Power data at all, so I started poking around and found my Connect IQ Power field had completely disappeared from my data screens, replaced by a timer field. I’ve had to restart this watch many times for the music issue, but this is the first time I’ve had my data fields change on their own.