Phantom routes load index template, no 404 and no errors
Thanks to P&amp;T via a support ticket, this issue has been resolved.

Basically I just had a structure which, some point, I had used as my navigation and was causing a conflict. Something which I just completely overlooked.

From P&amp;T via a support ticket:


  The issue seems to be in your Navigation structure. You have "Entries in this section have their own URLs" turned on, but you do not set a template for the section. So, when a user requests 'search', which is an entry in your Navigation structure, Craft defaults to show the index.twig template.