Watch 4 Sleep tracking not so accurate

[Stylos]

I woke up in the middle of the night to eat something small and the watch thought I finished sleeping for that night.

I went back to bed and slept deeply for another 5 hours. This sleep was not registered.

[AndrewL]

@Stylos: If you head to Samsung Health > Sleep, were your sleep patterns separated into Awake, REM, Light and Deep? If so, did it record the remaining 5 hours as 'Awake'? If the measurements were separated into Restless, Light and Motionless then try heading to the Health app > Settings > Measurements > Heart Rate > Measure Continuously to see if this helps.