Although I have a 404.php file in my custom template directory, anytime a 404 is thrown, my site goes to page.php and displays nothing. The title of the page is 'Page Not Found' because it's trying to call the page title and my side bar (which should show the current page and any parent or sub pages) shows links to every single one of my pages.
As a work around for now I have used the is_404 function to display an error which works just fine however I don't understand why the custom 404.php is not being called. I am using php include to show the content of the 404.php file.
I've tried to follow WP troubleshooting with no luck
perma link settings: /%year%/%monthnum%/%postname%/
Not sure what other info would be useful for troubleshooting.
Again, the page that you'll see if you try to go to a page that doesn't exist is the page.php file.