Operating my phone earlier it kind struck me for a possible reason, how come some users state their device(s) are fine and without any stuttering when scrolling. Devices are drawing the pixels with the same method, but something else is different - how we interact with the touchscreen and initiate the scrolling. We never agreed and or stated in our reports how we interact with the screen when the stuttering or lack of it occur. Because you can swipe the screen/list/page and release the finger, or you can keep sliding with the finger pressed to the screen. Now here's the interesting part. If I slide a list and leave my finger off, the scrolling is way less prone to frame skipping, then if I scroll with the finger on the touchscreen. There are still frame skips that weren't before in third party apps with lists with both cases, but less if leaving the finger off. So there's a possibility that the system in iOS 9 somehow makes it even worse when having to detect the finger on the touchscreen.