something strange happens. I work in Sketch and using Sketch to prototype and collaborate with customers. I have observed in last couple of projects that, after I upload homepage mockup (1600x2000px, for example), when I start scrolling down, it (automatically) freezes the scroll for the screen height size (some first 1080px of the mockup height) and than I need to scroll once again toward bottom so it continues scrolling until the footer of the mockup.
On some projects, it is continuous, on other is not - and I don't get it. Why is it freezing? I have observed this after I changed my iMac (bought new 4K), but still, on older projects, scroll is working perfectly, on new - I need to try scrolling twice until I enable it work. I am attaching examples.