The argument is that they didn't make their best effort, because they couldn't have possibly done so in only 3 days.

To be honest though, a lot of the questions were checkboxes. Did this device infringe, Y/N...

Once they had their criteria for evaluating infringement, they could hammer through the devices pretty quickly. I suspect that most of the deliberation was on if the patents were valid or not. If so, how then to evaluate if a device infringed?

I'm more curious to know how they determined damages... it seems like there should be a worksheet or something on that.

There's no way of knowing, but having served on a jury where the foreman was a lawyer (he only handled civil cases), I think the most likely scenario was that most of the jurors just followed his lead.

People tend to defer to perceived experts, which is why I find it odd Samsung's attorneys didn't catch this guy.

If they didn't know about him, they were incompetent.

More likely, they knew about him and made a bet he would side with them. They were wrong.

I read once about a case where the foreman on the jury (in a personal injury suit) was both a lawyer and a state senator. The judgement was set aside on the basis that he exercised undue influence by explaining the law to other jurors (thus usurping the judge's role).

Of course the law is full of funny cases (like the time the Supreme Court filed a per curiam, and then along with it a unanimous partial concurrence). Figuring out what was meant there is... well, something lawyers can argue about forever.

Or they knew about him and made a bet that he would taint the decision and get the case dismissed on appeal in front of a judge, who understands and appplies law better than civilians.