404 pages aren't being served for incorrect urls ending in .php

[Joobs]

I have a weird problem on a clients server. If you type in an incorrect url which ends in .php it doesnt show a 404 page and returns a blank page with a 200 header.

www.example.com/nothere/ - gives servers 404 page
www.example.com/nothere.html - gives servers 404 page
www.example.com/nothere.php - gives blank page with 200 header.

Any ideas what is causing this? disabled all my htacess and i removed my CMS files...

 

[Joobs]

It's an apache server.

I've contacted my clients host, but so far he hasn't been able to solve the issue.

 

[Joobs]

I'm guessing it's fixed as it's showing me a 404 error.

example.com isnt my website! i was using it as an example...

 

[Joobs]

directories and html files that dont exist get forwarded to the error page specified (the url actually changes, I thought it just serves that file but the url should stay the same?)

php files that dont exist still produce a blank white page