Data disappearing, not syncing

Hello,

I'm having an issue with disappearing data. For example during the day I can see the HR data is being monitored and logged and HR graph displayed on the watch face as expected. But then at some point it disappears. If I didn't sync with phone then the data since last sync is lost. Sometimes this erases an hour, sometimes whole day. This affects all the data collected by watch including hear rate, stress, steps body battery etc.

Anyone experiencing something similar? For example today, during the day I could see the data on the watch, but then at ~20:00 it got deleted and can't be found in the phone app either.

missing heart rate data