Cannot show permalink results in admin

[robrecord]

When I try to filter custom redirects in the admin, or take any bulk actions, I get nothing except for the following error:

Warning: Cannot modify header information - headers already sent by (output started at /srv/www/example.com/current/web/wp/wp-admin/includes/template.php:2546) in /srv/www/example.com/current/web/wp/wp-includes/pluggable.php on line 1416

Warning: Cannot modify header information - headers already sent by (output started at /srv/www/example.com/current/web/wp/wp-admin/includes/template.php:2546) in /srv/www/example.com/current/web/wp/wp-includes/pluggable.php on line 1419

This indicates that X-Redirect-For header is being applied after the page template has started being output; there might be a redirect call or a redirect filter happening within a hook at the wrong lifecycle stage.