I haven't, looked all over for a solution through settings but nothing. Fixing screen size doesnt do anything besides adjust both sides. I factory reset it and starts off the same way with the split screen.
Hopefully this helps. I had a split screen and I remembered this reset combination from youtube. I just tried it and it worked. Press the home button 5 times, then the up button once, then the reverse button twice ,and then the forward button twice. Dont do it too fast. Hopefully it works.