The XML insertion doesn't work properly. For one thing, they're using an old version of my syntax highlighter that doesn't work properly with element names with periods in them (even though I sent them the update months ago).
A much bigger problem is the fact that the editor likes to turn everything that looks like a link into a link. So you end up with <a> tags around links inside a code block, which tends to happen a lot with XML namespaces.
Finally, sometimes the editor just arbitrarily decides to forget the new lines in a code block.