HTTPS page returning HTML source and header rather than content?

Question

I'm building a web app with PHP and Python (The site has SSL) and once in a very long while, randomly, the page returns the header message followed by the HTML source, rather than showing the page's content.

This happens sometimes once out of every 30 times I load the page, or other times once out of 500 or so times.

It's very random, too.

Other times it renders just fine.

Here's what the header looks like:

HTTP/1.1 200 OKServer: Apache/2.2
Content-Type: text/html; charset=UTF-8
Date: Wed, 22 Feb 2012 10:40:33 GMT
Transfer-Encoding: chunked
Connection: Keep-Alive

66c2

The 66c2 changes randomly