Vivoactive - Incorrect step count

It's not really a "bug". It's more a limitation of the technology. Your watch needs to guess steps from movement from something on your wrist. Sometimes it includes steps it shouldn't and sometimes it misses. As for driving, it really depends on the roads and how you hold the steering wheel. I usually wear mu vivosmart on my left wrist and hold the steering wheel with my right hand.

To be honest, as far as I know, when driving, I've only seen steps counted 1 time. There may have been other times but it was minor enough that I didn't notice. I do get steps counted on my subway though. I also noticed about 200 steps counted while applauding at a Broadway play. Walking usually gives me 6,000 steps per hour while cycling gives me about 900 steps per hour.

The point is to get an appropriate activity level for you. If you know that driving will add x number of steps, add it to your goal so that you don't cheat.

Found this too- sat as a passenger in the back of a car, step counter ticks away without any movement...

There may be no movement by you, but it's picking up movement based on vibrations such as going over bumps or rough road. All activity trackers that track steps do this, as they can only guess if you're moving.