Trying out a new 255 (non music) with a hiking trail course I uploaded. I'm wearing just the watch and when I go off course I expect to get vibration alerts. But it seems very hit and miss whether I get them even when I'm 50+ meters off course according to the display (and my own knowledge of where the course was plotted).
Is there any documentation or FAQ on when notifications occur, how frequently and whether you get notified when back on course?