I started two manual sessions with my bike outside. It first started tracking HR and suddenly it stops giving me HR feedback.
The second time around it didn't even start tracking HR, just distance and duration.
I noticed that at home when I sleep and wake up, the green light is out and not blinking. I have it track continuously.
Why this randomness?
With optical heart rate sensors you really have to make sure you are wearing it correctly. Two finger widths away from your wrist bone and fairly snug. The watch shouldn't be able to move at all. Samsung watches are particularly sensitive for placement. I have been a Garmin tester for years and had no issues at all.
Sorry that's not it. On spinning bike it was slipping down all the time due to sweat and it still tracked correctly and on paar with the machine's HR.
The stop in HR tracking should be corrected. I mean the light stops completely blinking. No feedback whatsoever. Even when I place it correctly after I realized it's not tracking.
I have 44mm lte version and same problem + when i downloading app update on lte the watch is overheating can't make a call 30sec and disconnected and not dialing,the lte signal is poor near a forest always lost the network if i trouble can't call help or the watch battery die because battery life is trash,this watch is totally garbage for fitness and in a village,just in city no sport exercise just show your friends you have the Galaxy watch 4 and can make pay on the watch nothing more!