Activity Feed is blocked by IE 9 when there are emails scanned by Symantec Mail Security

Hello,

We are seeing a peculiar issue, where the activity feed present in the case / contact (or any other entity) is being blocked by IE 9 whenever this record has an email scanned by 'Symantec Mail Security' attached to it.

 Below image has the content attached by the anti-virus scanner.

If we change the IE to act as IE 8 using the developer tool kit, the activity feed shows up.

Has anyone faced this issue before? If so, how can I resolve it?

Is there any setting of IE, that we can change to fix this?

We are using Dynamics CRM 2013 SP1 - UR 2.