You usually don't see a first-degree murder conviction reversed for juror misconduct. But for every rule, there's an exception.
As today's opinion proves.
It's possible that the defendant will get convicted of the same offense (first- rather than second-degree murder) at the retrial. But maybe not. It's far from an open-and-shut case regarding premeditation.
Which is why there's prejudice here as well.
Regardless, not really worth shooting the guy over a $1200 debt for stucco repair.