The rendering of charts (https://en.wikipedia.org/wiki/Module:Chart) is problematic when the chart is near the bottom of a page. On the current version of https://fr.wikipedia.org/w/index.php?title=Sp%C3%A9cial:DownloadAsPdf&page=Insectivora&action=show-download-screen for instance, which includes a pie chart, the filling color starts as a square area at the bottom of page 3 while the circle is on the top of page 4 with the center of the circle where pie slices meet being shifted up, near the top of the circle. It is a bit hard to explain it with words (plus English is not my native language); just have a look to the PDF file rendered :)
