Even if it’s true doesn’t automatically lead to a mistrial.
It depends on when this post was made and when the ‘cousin’ told her relative that the verdict would be guilty on all counts.
If it was concurrent with the verdicts announcement or even within an hour or so, then there’s no need for a mistrial........
Pssst! The day BEFORE the verdict was delivered. The post was on May 29 and the verdict was delivered on May 30.