I've had my fitbit one for 3 years, and only for this last week has it started to exhibit the behavior complained of in this thread.

While in my pocket, in the rubber clip, the device apparently shuts down. When it's in this state, pressing the button produces no display; holding the button down for a few seconds causes the device to awaken and display "FITBIT 6.60" (so I daresay it was for all practical purposes "off" prior to that point). The time is wrong until a re-sync resets it. The "wrong" time is almost certainly the time at which it shut down, judging from the activity recorded (and not recorded).

There's clearly a problem here - one that is experienced by a number of users.

I have reset the device several times now to no avail.

I should mention that I normally sync to my iPhone, but sync'ed to my MacBook prior to the problem appearing for the first time. During that sync, I noticed a message about "updating" - but I don't know what was being updated (the app or the device or both).

There are several threads in which the same behavior is described. It would be helpful if fitbit could provide links in these several threads that point to a solution to this problem, if there is such a solution.