Lose map when out of cellular network.

I dont understand why, but i wanna use this app when i am out in the desert and out of cellular signal.
I tried twice. Once in the san bernardino mountains (california) and it worked. It was very useful.
The other time in Jawbone (Mojave Desert, California) and it kept on losing my position and the map. So pretty scary as i ended all by myself and lost as i was relying on it to get back to camp.
Very unreliable. I will give it another try...

ViperX10 about GPS Tour