在卸载所有非重要扩展并清除所有可能的缓存以及几个小时的调试后，我们发现了问题:frontend_editing"扩展 - 仅当用户已登录后台！

After uninstalling every non-vital extension and clearing every possible cache and a few hours of debugging we have found the problem: the "frontend_editing" extension - only if the user is logged in into the backend!