Because the way SSAA works, it renders the game at a higher resolution internally and downsamples it to the target resolution prior to displaying it. Basically like nVIDIA's DSR (which is, in fact, a form of Ordered Grid SSAA). It works wonders on real-time 3D scenes because it applies texture anti-aliasing on top of geometry anti-aliasing; however, for 2D images like PoE's backdrops, it introduces blur (2D pictures must be upscaled to be rendered at a higher resolution and upscaling leads to blur).
Hi new version of injector files released . I updated files . Maybe this one will help to you .
http://1drv.ms/1yOv1WX