Cavor on "[Plugin: WordPress SEO by Yoast] Warning: Cannot modify header information inside sitemap"

Hi,

I have these warning in the sitemap since last update (1.4.10) :

Warning: Cannot modify header information - headers already sent in /www/wp-content/plugins/wordpress-seo/inc/class-sitemaps.php on line 711

Warning: Cannot modify header information - headers already sent in /www/wp-content/plugins/wordpress-seo/inc/class-sitemaps.php on line 713

Warning: Cannot modify header information - headers already sent in /www/wp-content/plugins/wordpress-seo/inc/class-sitemaps.php on line 714

http://wordpress.org/extend/plugins/wordpress-seo/