I've seen this same subject listed by other folks in this string. I've had a fitbit charge since about 2016 and now on the Charge 6, this is the first time I've having this problem. I thought maybe it was because of daylight savings time as the problem first started happening for me yesterday. I have the latest version of the app and firmware on the charge 6; tried forgetting the charge 6 from bluetooth, removing the app from the phone, restarting the fitbit and reinstalling the app and reconnecting the charge 6 via bluetooth and still not able to change the hours of movement. is there any fix for this?