I am experiencing this too and thought something was wrong with my shield (I’m still unsure if this is normal behavior). Try pressing S1 button after everything automatically shuts down. This boots the pi back up and keeps it alive.
@ensar Is there a reason the unit does this? Can we keep the pi powered when power is first installed?
Edit: Perhaps it’s only when a battery is not installed? In spite of battery presence, I would still like to know how to change this if possible.