jQuery/FireFox selection bug

jQuery/FireFox selection bug

I have a snippet of XML.
var xml = $('<card><state><foo>1</foo></state></card>')[0];
On Safari, this works:
console.log( $(xml).find('card foo').text() ); // prints '1'
On FireFox, it does not (returns empty string),
but this works:
console.log( $(xml).find('card').find('foo').text() ); // prints '1'
I've worked around it. But it looks like it may be a jQuery bug.
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