[spectrum_7]

Well, no sooner than I ask, I figure it out… I forgot to wrap the add_image_size in a function and make sure it fires after the priority that is set on the function that created the original featured image size.

	// Custom cropping on Interface featured image
	
	add_action( 'interface_init', 'override_featured_image', 30 );
		
	function override_featured_image() {
	
	add_image_size( 'featured', 670, 300, array( 'left', 'top' ) );
	}