The line behind the view - were you using bloom & glare? Those won't currently work across the "seam" of a pano (one seam in a spherical mode, multiple seams in cubemap mode). The pinching is most likely due to the spherical mapping, that will happen at the poles - as you can see in the "flattened out" version, the top and bottom of the map are very stretched and distorted when using spherical mapping. That could be avoided using cubemaps (though note that at present, cubemaps aren't supported in the Corona VR app).
