Affected devices (all show the same problem): 1x iPhone 17 Pro Max 2x iPhone 18 Pro Max 1x iPhone 18 Pro Many demo iPhones at several Apple Stores Current iOS version: 27.2 Issue: Vertical scrolling inside apps frequently stutters and drops frames. It happens in many, many apps, including Apple's own App Store and Apple Store apps. During a normal flick-and-decelerate scroll, the content repeatedly freezes for one or more frames and then jumps forward. Because this reproduces on four of my own devices and on many Apple Store demo units, I believe it is a widespread, system-level issue, not a defect of a single device or my settings. Impact: I have been living with this for more than six months. I use my iPhone heavily every day, and the constant stutter has made using it genuinely distressing. Everything else about iPhone feels excellent, which makes this problem even harder to accept. Steps to reproduce: Open the App Store app (or almost any app with a scrolling list). Scroll with a normal flick and let it decelerate. Observe repeated hitches during the scroll. Measurements: I filmed the screen with a second iPhone at 4K 120 fps and measured content movement frame by frame: iPhone 18 Pro Max, third-party video feed: about 4 hitches per second of scrolling, about 4% of frames dropped, mostly single-frame drops. iPhone 18 Pro Max, third-party social app list: about 11 hitches per second, about 12% of frames dropped, at a regular rhythm every 6-8 frames. About a third of the stalls last 2-3 frames, and the content does not catch up afterwards. iPhone 17 Pro Max, third-party comment list: about 5 hitches per second, about 8% of frames dropped, including several full freezes of 50-75 ms. Expected: Smooth 120 Hz scrolling, as ProMotion is designed to deliver. Is Apple aware of this issue? I am happy to provide videos, frame-by-frame data, or sysdiagnose logs.