Any actions logged by the TMG Firewall that are not Allowed, Denied or Failed are grouped into 'Other' on the Dashboard. This includes actions such as Established, Terminated, and Intermediate. For the full list of actions see http://technet.microsoft.com/en-us/library/cc441730.aspx
You can use Alerts to get an idea of the types of Firewall Actions being classed as 'Other' on the Dashboard. Go to Settings | Alerts | Add Alert, and configure an alert with the following options:
- Action not equal to Denied; Allowed; Failed
- Alert Header - Show: Action
- Alert Evidence Table: What ever you like, but try Rule and Source IP.
Go to the Alerts tab and group by Alert. You should start to see alerts showing the firewall actions other than Failed, Denied and Allowed.