Since the 14.17 update, the FR955 is making my Garmin HRM Pro chest strap (8.80) to turn off. It usually happens when trying to download HR for finished activity.
The HRM turns off and won't turn on again, even for bluetooth connection with the smartphone or other devices.
The only way to bring it back on is to open it, remove the battery and place the battery back again. Removing the strap from the watch menu and pairing again didn't help. Neither did resetting calibration data.