There's nothing to worry about since no one is getting into your phone nor hacking it. If you've set up your phone's location services to Always and the mileage to track automatically, this is why your mileage is operating even if you're at home.
I suggest, modifying the Location Services of your phone, and turn off the Auto-tracking feature whenever you're at home. This is to prevent tracking unnecessary miles.
To give you some tips on how to manage and use mileage, please see these links attached:
On the other hand, for those miles that were tracked at home, you may categorize them as personal. You might consider checking this article for more details about the categories in QBSE: Categories in QuickBooks Self-Employed.
Know that I've got your back if you have any other questions. I'm always here to lend a helping hand. Wishing you all the best in everything that you do, brightsidea.