Symantec DLP 11.6.0 not enforcing block on Clipboard Copy

I'm currently running an environment at 11.6.0.x and in the process of deploying new endpoint DLP policies.  For some reason, when I create a policy to block copying data to the clipboard, it will pop-up a warning, but does not clear the clipboard.  (You can copy an SSN, you get a warning, but can still then paste the data into another application)  Is this the intended affect, or is my rule written incorrectly?

For testing, I have the condition rule set to: Clipboard (Protocol): Protocol is Clipboard. 

And the response is:  Endpoint Prevent: Block