I am having the same problem, and I purchase my Fitbit Luxe primarily TO track my sleep patterns. When I first started using it, on 6/23, it worked fine. But since 7/7, it has not tracked my sleep all on 7 days, and returned wildly inaccurate readings twice (43 minutes and 1.5 hours).
I tried all sorts of things to troubleshoot this myself - re-synching, cleaning the sensors, wearing it in different positions (higher on wrist, on inside of wrist), changing sleep sensitivity settings, turning it off & on, restarting my phone, removing the app & re-installing it, turning off bluetooth and restarting it, re-pairing, and even doing a factory reset (which never actually deleted any data though, so not sure it was even successful) - but nothing has worked.
It is tracking steps and heart rate fine. Battery is always good - I never let it get below 60% - and I charge my iPhone all night, every night.
I contacted support via chat yesterday, but the person on the other end said he couldn't help me and was going to transfer it to higher up support, who would contact me via email - but not one has yet.
Feeling really frustrated.
