Gear Sport telling me I ran farther and faster than I actually did

[Android Central Question]

I just got a refurbished device, excellent condition apparently, and just tried it on my usual run route that I know is almost exactly a mile and a quarter long. However after I completed the run, the sport told me that I ran 1.7 miles at an average of 10 mi/minute which is a lot faster than I know I'm capable of (I'm new at this so I'm slow). Anybody else have this issue before? Should I be concerned or will this go away soon?

For reference, the Sport was connected to my phone which I brought along with me, and I started the run through the Sport which synced with Samsung Health.