First, clarifying Place abilities are CBN in the phase after they complete. This is because any instant ability is CBN in the phase after it completes, and Place is instant (and Hopper completes in the phase).
See
this thread for a discussion of what can happen if you play SoG
during the phase in which it is drawn. The consensus
seems to be that you cannot play dominants during the draw phase, but that if it were drawn in a different phase and SoG were played, it would first negate the Hopper and send it to the original Land of Bondage; at that point, if the player using the card would be able to rescue from that LoB (since you cannot rescue from your own), they do so.
I do not see anything wrong with that interpretation. In fact, you should be able to target your own Lost Souls with SoG and negate them (though not rescue them, since that is against game rule), so as they point out, if your opponent drew Hopper outside of draw phase (such as off of a hero draw) and placed it in your territory, then
during that phase you could target it with SoG. It is now negated, so it returns to the original LoB (where it was placed by game rule before its ability placed it elsewhere). Now it can be rescued, so SoG rescues it.
In reverse, if you target your own hopper you just placed in an opponent's LoB
in the same phase, you negate it, it returns to
your LoB, and SoG no longer rescues it.