The information can be found in the FAQ section of the Canon Europe Self-Service site. [UPDATE: Canon USA has issued a formal statement as well.] More information on the history of this issue can be found on this page. The following information is from Canon Europe:
Why do I experience inconsistent Auto Focus (AF) behaviour with my EOS-1D Mark III?
Case Id: 72525
The focus or AF tracking is inconsistent when using the Artificial Intelligent (AI) servo continuous shooting mode under high temperatures in particular.
In the digital SLR camera, EOS-1D Mark III that was launched in May this year, Canon has found that some cameras have an adjustment problem with the mirror for AF. The adjustment problem means for the affected products that the focus is not stable or that the Auto Focus tracking is not right when using the AI servo continuous shooting under high temperatures in particular.
The products that could have this problem can be identified as explained below. If the serial number on the bottom of the camera is between 501001 and 546561, it could contain one of the AF mirrors with the adjustment problem.
For customers who have affected products and are experiencing these problems, we are making preparations to offer free of charge repairs planned to start from late November. We will announce additional details about the repair process on our Web site as soon as they become available.
In case you have questions about this or other issues, please contact Technical Support using the button at the end of this message. Alternatively you can also call our Helpdesk. Please click here for the phone number.
We offer our most sincere apologies to all affected customers who have been inconvenienced by this issue.
Last modified date: 01-Nov-07
[tags]canon, 1d, mark iii, focus, fix, problem, recall[/tags]