Test device: Pixel XL

The PageView contents are rendered correctly on the initial render but once you start scrolling they become corrupted. They will remain this way even after the scrollable "settles".

The following are examples of text and a Widget near the edges of a DecoratedBox:

From @abarth (on Gitter): "it sounds like a problem in the raster cache that once we cache the texture for the page we draw the ugly version".