TED Talks app - video error and solution

When trying to play a TED Talk video from the iPhone or ipad app would get a

"Playback Error - An error (-11848) occurred while playing this video."

The following in the Web Filtering log:


2013:02:16-16:03:03 net httpproxy[4845]: id="0001" severity="info" sys="SecureWeb" sub="http" name="http access" action="pass" method="GET" srcip="10.0.100.29" dstip="8.26.215.126" user="" statuscode="200" cached="0" profile="REF_DefaultHTTPProfile (Default Proxy)" filteraction="REF_DefaultHTTPCFFAction (Default content filter action)" size="0" request="0x15949370" url="http://tedhls-vod.hls.adaptive.level3.net/bumpers/hls/video/in/None-950k.ts" exceptions="" error="client connection closed during scanner run" country="United States" category="178" reputation="neutral" categoryname="Internet Services" content-type="video/mp2t" application="http"


"Bypass content scanning for streaming content" was selected but gave no joy.

To correct this I had to add a Web Filtering exception for..

tedhls-vod.hls.adaptive.level3.net and skip checks for Caching and Antivirus.
(removing either of these skips would cause the problem to return)

Can anyone explain what is happening?

Tom