Start PowerPoint. Draw a Pie shape (UI Partial Circle) that is wider than high. Add some text to the shape with alignment left. Copy that shape and insert it. Save the file.
Now open the file markup and replace in one of the shapes the prstGeom with a custGeom and the markup from presetShapeDefinitions.xml from the ISO_IEC_29500 standard.
Reopen the file in PowerPoint. Notice that the text is out of place.
The markup from presetShapeDefinitions.xml has in node <pie>
the child element
<rect l="il" t="ir" r="it" b="ib" xmlns="http://schemas.openxmlformats.org/drawingml/2006/main" />
But it should be
<rect l="il" t="it" r="ir" b="ib" xmlns="http://schemas.openxmlformats.org/drawingml/2006/main" />
.
You can test it, when you manually correct it in the file markup.
I could provide the provide a test file. Sadly I cannot attach it here.