Since he was there for a decade and his participation in the body was specifically illegal, were there any tainted single vote majority decisions during that time? A lovely field day for the barristers!
The Greens tend to vote as a block and with the numbers they’ve had it’s unlikely there were any cases where his single vote made a difference. It wouldn’t matter anyway under Australian law - a Parliamentary vote stands once it is announced by the Speaker of the House, or the President of the Senate (or the person acting in those roles) to ensure certainty, even if irregularities occurred, they can only be challenged at the time.