I'm using Zen 6.x-1.0-beta3.
When Drupal is sitting behind a reverse-proxy (ie: nginx), error pages (404 or access denied) will have 4 hex characters echoed above the page html content. The characters are seemingly random (ie: "24cb").
This may not sound like a Zen problem, but the problem only occurs when using the vanilla Zen theme, or any sub-theme of Zen.
Does Zen have any logic in it that could possibly result in characters echoing above the HTML content?