When we are attempting to render a line chart using a Polygon with around 11,000 points in an area around 60 pixels wide with anti-aliasing enabled we get some rendering artifacts. It seems to be extending certain segments further along the x-axis. The exact shape of the artifacts depend somewhat on the exact distribution of the data points along the small area, but they are usually of the same form.

Artifacts of the same nature are seen when using a Path2D with similar density of paths to pixels.

Using several small objects like Line2D objects for each individual line doesn't cause those rendering issues.