I see what you are saying and I agree partly. The ITC claim construction very well may be a matter of law and reviewed de novo by the CAFC. However, if the claim construction by the ITC is found to be supported by substantial evidence, then that may make it a factual finding. District court claim constructions are given no deference. So it's not a certainty either way. I think you raised a good point that needed clarification.

As for ITC rulings, they certainly aren't given deference.

I'm not sure about past cases that fit the Patriot scenario. But here's a case that is recent where the ITC claim construction was not given deference and the ALJ was reversed in part. http://www.kslaw.com/library/newsletters/ITCSection337Update/2013/October_17/MicrosoftCorp.pdf