Garmin 62 Issue ( Current Position Frozen )

I have a GPS Garmin 62s and I use it for my outdoor trails.
It works well but from time to time the current position indicator ( black triangle ) remains frozen at the same position for 1 or 2 minutes although I am continously in moviment. After that, suddenly, it "jumps" to the correct position and continue working well.
Surprisingly, the current track ( the one I am doing and saving ) is ok, so you can see the black triangle frozen in a given position and the end of the current track in another one.
Not a concrete pattern for this behaviour, looks like it is random ( from time to time ).
I tried to refresh the screen ( pressing zoom in / zoom out / quit / page ) but it remains frozen until it decide to update itself ...
Also, I updated the device with the latest firmware, but still the same problem.
So looks like the device works ok calculating the current position ( the track is ok ) but it doesn't update the black triangle for a while.
This is an annoying problem because sometimes I am in doubt of in which position really I am.
Is there anyone that has the same problem? Any solution?

Thanks