High bandwidth usage but only showing on External if

Question

I noticed our internet pipe was maxed out on the downstream, so I logged into the UTM and noticed the External interface was pegged, but there was little activity on all the other interfaces. The traffic was tagged with the "Akamai" application name over port 80. Does Up2Date use Akamai for content delivery? I'm trying to figure out where the traffic originated since all of our internal interfaces were twiddling their thumbs while only the External interface was being hammered. It looks like, according to the flow monitor, that the traffic is originating from the UTM itself.

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BAlfson · Accepted Answer

What happens if you disable/enable Web Filtering when you see this - does the traffic stop and then restart? If so, then it's not the UTM getting updates. I've seen this happen when the HTTP/S Proxy is trying to download a large file, the server thinks the connection is lost and then the UTM starts trying to get the same file again. Did that help? 
 Cheers - Bob