I edited this page: http://community.jboss.org/wiki/TestsuiteChanges
After saving, all text originally appearing as a code disappeared. See the comparison:
http://community.jboss.org/wiki/TestsuiteChanges/diff?secondVersionNumber=15

Note that this regards the "code" migrated from some old wiki, NOT the code block produced by the editor.
2nd note: I hit this before, but I couldn't find the bug, perhaps I didn't fill one. See the-core.