(7) In a mandatory appeal, any party may file a motion to dismiss the appeal based upon lack of subject matter jurisdiction, mootness, untimeliness, or other cause unrelated to the merits of the appeal. The court may, without the issuance of any order, defer ruling upon the motion until after briefs are filed and oral argument, if any, is held. Any order or decision by the court disposing of the case on the merits shall be deemed to be a denial of any pending motion to dismiss. In a mandatory appeal, the supreme court may at any time, on its own motion and without notice or on such notice as it may order, dismiss the appeal based upon lack of subject matter jurisdiction, mootness, untimeliness, or other cause unrelated to the merits of the appeal.