Sony have admitted there is a problem with this-here is their statement:
"Response (Elizabeth L.) 01/24/2011 08:22 AM
Hi colin,
Thank you for writing back. I have checked our bug database and confirmed this as a bug in this version of the software. We are currently looking to fix it and apologize for the inconvenience.
This error occurs when using the 1920x1080 format of Sony AVC when using AVCHD footage. If you render to 1440x1080, you will likely not see the issue. Some users have recommended that you run the file through tsMuxer http://www.smlabs.net/tsmuxer_en.html or another converter, then the footage works fine.
Also, rendering to this particular format using this method may work as well, as the footage will no longer be AVCHD when it is rendered to its final state."
"Response (Elizabeth L.) 01/24/2011 08:22 AM
Hi colin,
Thank you for writing back. I have checked our bug database and confirmed this as a bug in this version of the software. We are currently looking to fix it and apologize for the inconvenience.
This error occurs when using the 1920x1080 format of Sony AVC when using AVCHD footage. If you render to 1440x1080, you will likely not see the issue. Some users have recommended that you run the file through tsMuxer http://www.smlabs.net/tsmuxer_en.html or another converter, then the footage works fine.
Also, rendering to this particular format using this method may work as well, as the footage will no longer be AVCHD when it is rendered to its final state."