Recently, I loaded the Alpine Loop course from bikepacking.com. Last weekend, I rode the course with some buddies, all of whom have different Garmin units. The ENTIRE RIDE, my Garmin told me I was off course, to make a u-turn, and every few minutes would beep and then tell me it was recalculating. Only mine had this issue (my buddies' Garmins followed the course fine). What would be causing this?