My Fenix 5S Plus gifted a mile to me

I programmed a workout into Connect, loaded it to my watch and subsequently finished it. At the end of my workout, I carried on but noticed that a mile had been added to my overall distance. Looking back at Connect, it seemed like it glitched at lap 16. Anyone else experience this? And when I look at the map, it is accurate. ciq.forums.garmin.com/.../1467859.jpg