When a ScrollView has a style then it changes the way the scrollbar reacts when the scrollview changes size

When a ScrollView has a style then it changes the way the scrollbar reacts when the scrollview changes size.

In the example attached, the top scrollview has a modified style and the one below does not, scroll both to the far right. Then resize the window by about 3x the height. Then scroll across to the left, note the top scrollview does not scroll correctly anymore.