I have a lot of problems with the device since a few weeks. I was always amazed with the fact that they Vivosmart 4 could track my exact sleeping time, it even recognized just laying down (while watching a movie in the evening etc.). But right now it's just horrible and starts tracking sleep at 8 p.m. Heart rate while sleeping alsof dropped significantly from 57-60 to 50-53 with no reason. When doing a normal bike tour, I quickly get 140-160 bpm. Only thing that's still 'accurate' (behaving like before) is the Pulse Ox. Fix this please