Can I propose an alternate conspiracy theory?
The NY State Supreme court looked at the whole trial and the backlash and basically came to the conclusion that this who effort was a mistake and needs to go away.
So they put together an easy “out” via the mistrial path. IOW, get rid of this before we have to rule against the judge.
The Supreme Court in NYS is a trial court and not the highest state court, or court of last resort, the Court of Appeals is, I believe. Also, Judge Merchan is an acting justice of the NYS Supreme Court, though I’m not sure that is the capacity in which he heard the case.