It took me a long time for Sony to admit the following in an email to me....
I have had an update from our Product Quality Department and they have been able to reproduce this symptom, they are looking into the issue, however I have not been given any time scale.
they have requested that i get the software version of your TV, if you go to Digital Setup Menu it should be listed.
I sent them the software version and basically they accept there is a problem but have no solution. Their final communication to me after several emails was....
I have checked and the issue is still under investigation within Europe, we can only wait on them coming up with an update, however as I advised before this will take some time as they have to narrow down what is going wrong and then create a new software pack, test it, test the implementation and the launch it via the DTG. I am sorry but this could take a month or two, it is a very weird software glitch and in most instances it would never happen, I understand it can be reproduced by suppling un-natural images or down scaled video, however that is not a fault. we are working as quickly as possible but there are many procedures to go through to make sure everything is correct.
I am sorry I cannot be of greater assistance on this occasion, however I hope that my e-mail has gone some way to clarify this matter.
Use the HDMI and a set of speakers I would suggest.
Regards
Fitz