The Calypso Editor is having different behavior when using [code] to languages like XML, when you switch between the editors. If you add the content on the Visual Editor, it changes the code, and if you add on the HTML Editor looks like it's resolving the code. Here is what I did:

1 - Adding the code on the HTML Editor, then changing to the Visual Editor:

2 - Adding the code on the Visual Editor, then changing to the HTML Editor:

3 - Another code, added using the HTML Editor, then changing to the Visual Editor:

4 - Another code, added using the Visual Editor, then changing to the HTML Editor: