The cnet article was the original source for the Groklaw quote. The juror in the quote didn't mention anything about possibly going back to the issue. We don't know if cnet didn't run that part of the quote (why would they, they get more clicks with more controversy), or if the juror just didn't mention it. We do know that he isn't quoted as saying, "oh yeah, we never got back around to it".
And since they explicitly had to make the choice on the instructions (Y/N) on infringement, the safer assumption is that they did get back to it.
This is the same jury that awarded Apple $2M for a phone that, according to them, did not actually infringe upon any patents. Fortunately, the court fixed that up for them.
Given that they also have been quoted as not needing the jury instructions, actively ignored those instructions by indicating that the damages awarded were punitive rather than compensatory, and that they could have spent, at most, a few minutes on each of the hundreds of questions, it's hardly out of line to think that this verdict was rushed.
My understanding is that there were two jurers who were unconvinced about the prior art thing. It seems to me like what actually happened is that, rather than trying to convince those two jurers (i.e. coming to a unanimous decision), they just went with "majority rules".
Of course, there's no evidence to suggest that's what they did, but equally there's no evidence to suggest that they eventually went back to that question and debated it further.
Given that they admitted to ignoring the instructions on punitive vs. compensatory damages, it's not a stretch to imagine they also ignored the instructions on coming to a unanimous decision.
Instructions are advisory. They are meant to help jurors who are unclear of what the law says. However, they are not shackles on the jurors. Jurors are free to ignore them, and should ignore them when justice requires it.
For example, Jurors have the right to find a guy not guilty when caught red handed with marijuana simply because the law is unconstitutional. They have that right and that is intentional in our system. Judges on the other hand, tell jurors in their instructions that they "have to find them guilty if they believe he possessed the drugs". When judges do this, I consider it jury tampering, and unfortunately for innocent pot smokers, too many jurors listen to the instructions.
The problem with your argument is that jury nullification is designed to prevent unjust punishment. In this case the jury appears to have deliberately increased Samsung's punishment.
And since they explicitly had to make the choice on the instructions (Y/N) on infringement, the safer assumption is that they did get back to it.