Hi I have been using an older version of the HDMU build which worked fine, until I performed an update 3 weeks ago and first noticed the problem during the champions league final that was shown on a free-to-air channel ITV 1 HD. Over the weekend I have installed another HDMU image, build 10847 and I still have the same problem.
Please note that the problem does NOT happen or manifest itself on all HD channels. For example, during the champions league final, ITV 1 HD had the distorted problem, the same game was also shown live on Sky Sports 1 HD which did not have the same problem. I noticed the problem on ITV 1 HD last night and I will be able to re-create the problem - I am not sure how easy it will be for you.