The FAL in my Leicas won't snap back and I don't have a problem with that.
Now, after my own kind of snap, let me add that the FAL in my S2 seems to return to its place after I use it. Have you shot your newly acquired body? I'd be concerned if there were a spacing problem but, to be honest, I don't think there'll be any. After all, there isn't any problem with my M bodies.
Take care and go out with some film in your S2!