I recently "upgraded" from a Forerunner 230 to a Fenix 5+. The 230 made a decent fist of measuring sleep, giving stats that seemed highly believable. On the other hand, the 5+ seems lousy, totally ignoring any sleep you get before having to later get up for a quick call of nature for example. It also seems that I'm suddenly getting zero deep sleep most nights, and at best just a few minutes, according to the 5+, whereas I previously was getting 1-2 hours most nights as measured by the 230.
Are these known issues with the 5+?