Surprised to see that the OP didn’t even mess with scrolling – a staple nowadays, especially on touch devices.
For me it is lack of scrolling. With many domains that scripts should be loaded from blocked (umatrix) some modern sites show lengthy content but no scroll bar. It might be intended to set up the view by script depending on the device, but for sure it feels as if it is intentionally done to make visitors load/run the scripts.
It's probably because the script is blocking a modal window. When you clear the window, the scrollbars return.