Wow this issue has been ongoing for YEARS! I used to have a Charge 3 which would occasionally lose steps during sync (particularly after a long walk) and when its display finally died, I bought a Charge 5, thinking well, maybe this step-losing problem will go away. No such luck. It happened again today (and many other times too) after a hike. I notice also that when I look at the "Daily Steps" graph, the steps taken during the hike get clipped flat to a lower value. It's as if I walked at a perfectly consistent pace throughout the entire hike. This is clearly a bug in the interface between the app and the FitBit device itself. I suspect the programmer who understands this interface intimately has long since left the company and the new guard can't figure it out. Sadly, I don't expect this to be resolved anytime soon. This is due to the apparent default cycle of tech companies. i.e. Someone has a cool product idea, starts a new company, sales soar, features are added, new products are added, success causes chaos, founders get burned out, they sell the business to another company (or worse, "investors"), bean counters move in to maximize profits and the "soul" of the company is promptly destroyed. It just grinds for profit. This happens all the time. There are exceptions, but they are extremely rare. It doesn't appear that FitBit is one of them.
