Exchange 2010 Transport Rule based on incoming email subject

[HMCTech]

I set up a rule saying 'when the subject field or message body contains 'Your changes have been published to the website'' set the spam confidence level to -1

 

This was to try and stop emails with that subject being sent to captured spam with one of us having to then send it on. The subject of the email is exactly as I have put down but this rule seems to not work which is annoying slightly.