Recipient Filtering - Exchange 2013

Is Exchange 2013 Recipient Filtering  is broken ?

I have just come across an issue that when enabled, with the following config:

Name                       : RecipientFilterConfig

BlockedRecipients          : {}

RecipientValidationEnabled : True

BlockListEnabled           : False

Enabled                    : True

ExternalMailEnabled        : True

InternalMailEnabled        : False

If someone sends a message to a bunch of your users and one of them is invalid – none of the other recipients receive the message; it would be bounced. To make it more annoying Exchange receives the whole message before it is bounced, so it wastes bandwidth as well.

At the moment i have turned it off. Can some please advise me if i have missing something with the recipient filtering.

Thanks

Neil