Вот ,нашел!
http://masmap.org/forum/viewtopic.php?f=13&t=220Before you turn on the track-logging feature in the 60CSx, you must first ensure that Lock on Road is Off. To do this, go to Menu > Setup > Map > General > Change 'Lock On Road' to Off.
If you fail to turn off Lock on Road your tracklogs will lock on to the roads on the map rendering the tracklog useless.
И тут!
http://wiki.openstreetmap.org/wiki/Garmin/GPS_seriesHints
Be sure you have turned off "lock on road". (Setup -> Map -> Lock On Road = Off) otherwise your location can be very jumpy if you are walking next to a road. (and your GPX files will probably be contaminated with copyrighted map data!
Видимо,когда пользовался навигацией на дорогах,забыл отлключить эту опцию!
Но я думал,что эта опция влияет на только навигацию,а оказалось,что и на запись трека тоже!