Hi,
I had this problem on BD 2012 - and still have it with BD 2013 Beta.
Scenario:
Settings ==> Antivirus Settings ==> Active Virus Control - move the slider to "Aggressive". The text description indicates "Aggressive". See first attachment.

Close the BD window (click "X").
Re-open the BD window from the desktop tool bar (right click + Show)
Settings ==> Antivirus Settings ==> Active Virus Control - the slider is still in the "Aggressive" position but text now indicates "Normal". See second attachment.

Information about BD software level. See third attachment.

If you need additional information - I ran the support tool and uploaded the output a short while ago in relation to another issue - see This Post .
Let me know if you need more information.
Cheers
Ross