MediaWiki 1.15.1 + FCKeditor = Preview on first edit broken

I have encountered a problem with FCKeditor since upgrading the OpenOffice.org Wiki from MediaWiki 1.13.3 to MediaWiki 1.15.1.
I've tried both the "new" version of FCKeditor from here: http://www.mediawiki.org/wiki/Extension:FCKeditor_%28Official%29 and the older one from here: http://mediawiki.fckeditor.net/ with the exact same behavior.

If you have your user preference Edit option set to "Show preview on first edit", then with FCKeditor On OR Off, the Preview is not rendered correctly. Disabling the FCKeditor extension allows the Preview to be rendered correctly.

To see this in action, go to:
http://wiki.services.openoffice.org/wiki/Documentation/DevGuide/AppendixB/Useful_XHTML_Tags
and with your user preference Edit option set to "Show preview on first edit", edit the page.

Examples of the behavior:


I done a lot of digging and came across this bug: http://dev.fckeditor.net/ticket/2432 which has been closed, but does nto seem to be exactly the same issue (at least not as far as I can tell).

Is there anything I can do to correct this problem? Or anything I may have done to cause the problem in the upgrade process?