Php block messing with the page tittle
So I found an issue about this in the privatemsg issue queue, basically they are overwriting the page title when the form is embedded like this. So you need to use the code below to save the title before the form call and then set the title back to the saved one afterwards.

// Save the title.
$stored_title = drupal_set_title();
// Call the form.
print drupal_render(drupal_get_form('privatemsg_new', $recipients, $subject));
// Set title back to the saved version.
drupal_set_title($stored_title);


Here is the link to the issue if you want to do more research: https://www.drupal.org/node/1621198