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"Of course my <head> is ok" - sometimes it's not as obvious as clearly broken markup. The <head> is self-closing, so any HTML element that's not valid in the <head> will result in the rest to be considered as a part of the <body>. That can be a stray <img> that ends up somewhere wrong, it could be an <iframe> that a script injects to the top of the <head> during rendering. This is visible if you inspect the DOM of a page in your browser.