Fitbit Versa recording incorrect distance/pace

[jessicalb34]

 When I first got the versa it was spot on. I walk 3.9 miles at a 14.50 ish pace.  I have mapped it in my car and I know the distance.  Every once in a while it would screw up my pace and jump up to 19-20 min per mile but then by the next walk it would fix itself.  I have not changed anything and now it is consistently putting me at a 20 min mile and way less distance than I am actually going.  My friend, who walks with me, has an apple watch and hers is calculating our pace/distance correctly.  This is driving me NUTS and I don't know what to do.  Why did it work and now it doesn't when nothing has changed?  Does anyone have any suggestions?

Thanks!

Moderator edit: Updated subject for clarity 

[SilviaFitbit]

Welcome to the Community @jessicalb34. Thanks for letting me know the information that you used to get with your Versa. Sorry for the delayed reply. 

I appreciate that you've compared the data with your friend and mapped it with your car.

Remember that the data may vary between trackers because each device will use a different algorithm to track data. For Fitbit Versa, the connected GPS feature uses the GPS sensor on your nearby phone. Since your Fitbit uses GPS, and you track 1 or more runs using on-board or connected GPS, we evaluate that data to automatically update your running stride length. For best results, run at a comfortable pace for at least 10 minutes.

Note that when you're tracking an activity with GPS, Fitbit calculates your distance using GPS data rather than steps. If you begin moving before you get a GPS signal, the tracker will calculate distance using steps and stride length as described above until a GPS signal is found. You can learn more about it by checking these articled: How accurate are Fitbit trackers?

It wouldn't hurt if you try a restart and then continue tracking your walks. 

Let me know how it goes. I'll be around if you need further assistance.