So a lot of the scrolling behavior is a bit weird, I've narrowed this one down to a specific problem, though.

In the Heroes Played, if you click in the box and keep your mouse cursor stationary while scrolling down, then it stops abruptly after a few lines and stops being scrollable entirely.

This is oddly enough tied to your Mouse coordinate's Y-axis. That is, if your scrolling stops, you can move the mouse up or down and you'll be able to scroll again. If you move the mouse left or right, however, the bug persists.