You need to clear the browser cache, otherwise it will keep on detecting it until it auto expires in cache...
Thanks for your input, but unfortunately, clearing the Cache won't help in this instance. It's the Web Shield that is causing this issue. Every time a user gets redirected to "block*DOT*opendns*DOT*com", they will recieve a trojan alert.
We need an update from Avast ASAP to resolve this.
Kind Regards,
Stephen