I upgraded from a Vivosmart3 to a 4 - 2 days ago. I changed the preferred device to the new device. No other preferences where changed. Day one it tracked steps accuratley and combined data from old device. First night it tracked deep and light sleep and sleep pulse ox. Last night only deep sleep (and I was up twice) and no data for sleep pulse ox. No REM either night. In addition, yesterday it only tracked 207 steps?
Any ideas on what is going on?