Awesome but leaves lines after effect

I love this app! Quick and simple. Only thing is when using natural, sometimes theres a line through picture but when I click on other effect and back to natural it goes away. The overall effect is great but when you zoom up to view from photo album I notice they all have slight lines or distortion. Not sure how to phrase it. But I do love this app. One of my top favorites. Please fix! Thank you!

!NOMES? about A-HDR