I just noticed this week that after a run where I had the HR sensor enabled.
Situation:
1. HR Disabled before the session
2. Enable HR before starting the session
3. Ends the session
4. Disable HR monitoring from the watch
5. Status is show as off but leds are still on/blinking
6. Restart the watch. The status is shown as enabled
7. Disable the HR and now it is respected
Forerunner 955 non solar
16.17
GPS: 5.00
Wi-Fi: 28.05
CIQ: 4.2.3
BMX: 13.0.4
WHR: 13.00.04
ANT/BLE/BT: 28.05
TSC: 1.14
Sensor Hub: 25.63