Judge Koh had ruled on summary judgment (i.e., ahead of the spring trial) that Samsung infringed it -- but infringement of an invalid patent doesn't matter, and only because the jury was grossly misled about the validity of issued patents in general and Apple's patents-in-suit in particular doesn't mean that Judge Koh couldn't still agree with Samsung's post-trial motion and hold claim 18 of the '172 patent invalid. The legal standard is stricter in the infringement case (especially now at the JMOL stage) than in reexamination, where clear and convincing evidence is sufficient to reject a patent claim, but it looks awkward that Judge Koh held Samsung to infringe a patent claim that the USPTO probably wouldn't have granted if it had been aware of all of the relevant prior art.
Samsung has filed a document with the court to draw Judge Koh's attention to the decision.
"This Office Action is relevant to Samsung’s invalidity defenses for the ’172 patent, as described in Samsung’s Motion for Judgment as a Matter of Law (Dkt. 1896-3, Section III) because the USPTO concluded that the prior art identified in the Office Action is the same or in the same family as the prior art asserted by Samsung in this case."
This could result in Apple's $119 million verdict being reduced further or delayed if Apple decides to exhaust all appeals.