Do you remember the pedometer bug in Samsung Gear Fit I've discovered earlier ? It turns out that Samsung is a fan of this one and has the exact same bug in their S Health application.
The application doesn't block pedometer(e.g. steps counting) while performing other activities such as cycling for example. So in reallity it reports incorrect value for burned callories. At this time I call it bad software development practice/architecture on Samsung's part which leads to this bug being present.
Btw for more interesting bugs see Samsung Gear Fit Bug-of-the-Day.