<menuitem> content model

To the attention of Validator.W3.org/Nu staff.
While still waiting for you to process my previous request, I have to file
another bug report.
While validating a <menu> element in the popup menu state containing
commands in the form of <menuitem>, the validator expects them to be closed
as block tags:
<menuitem></menuitem>.
In html documents with the end tag omitted, each <menuitem> is considered
child of the previous one.
In xhtml documents, when the self-closing syntax is used, it's flagged as
wrong for the element.
In both cases, the end tag </menu> is flagged as wrong because there are
unclosed tags.
The spec (HTML5.1 editor's draft) states that <menuitem>'s content model is
"empty" and the end tag is omissible. So, shouldn't it be treated as a
<br>, <img>, <base> etc. element?
Thank you in advance and regards.
Andrea Rendine