scribu/wp-posts-to-posts — comment on commit 975a467b9390a37a75f6c117c758b98c93204a5d
File: admin/column.php line 27
By scribu:

Fixed: 67c174b8b7ea2ac0ea5a20c697c2a512b4ae9412

It turns out the extra space I was seeing was caused by another plugin.