I'm having exactly the same trouble with some ajax submits. When the submit content has the word "hentai" the server refuses to process it and throws a 403 - Forbidden error and additionally, a 404 - not found.
I'm using some blog-like commenting system that uses some Ajax, and lately I've found that if you write the word "hentai" the response is a 403 - Forbidden. The server refuses to submit the POST via Ajax to my PHP script and throws a 403 error.
Amazing.
But the most bizarre thing is that I can...