WCM tip #6: Use complete matching for catalog item URL fields
Managed Properties linked to Site Columns used as URL fields in catalog should have Complete Matching enabled for the catalog content to be retrieved properly.
As URL fields in catalogs contain text there is always a chance that the URL field of one catalog item could contain the text of a URL field of another item, for example a page about the Contoso company with the URL field set to contoso and a press release about the new Internet website for Contoso with the URL field set to new-contoso-website. As you can imagine, looking up the page about the Contoso company could return the press release instead as its URL field also contains the word contoso. In order to avoid such issues, Managed Properties that are linked to Site Columns used as URL fields in content catalogs should have Complete Matching enabled. This will cause SharePoint 2013 Search to match the lookup value against the whole value rather than only a part of it.