Livetrack - not starting when there is no mobile phone signal

Yesterday I commenced a route in a valley without any mobile phone signal.

Upon starting the hiking activity my Instinct notified me that Livetrack had started (it is set to automatic).

However, the Livetrack email link was never received by the intended recipients.

My only conclusion is that, under the activity commencement circumstances, that Livetrack does not 'kick in' once I had hiked through an area where there was a mobile signal (about 80% of the route).

Is this correct?

Thank you.