The jurors seem to have assumed that the foreman was an expert and gave his opinions undue weight. Another impression is that the jury didn't pay much attention to the instructions after the judge read them out.
I was on a jury at a simple trial. The entire thing lasted less than one day. The instructions were short. We had to go back into the courtroom to have the judge clarify the instructions. There were still some jurors who didn't understand the instructions after the clarification. I wonder how many of those jurors voted with the majority because they didn't want to come back the next day.