That timeout can be big...it didnt even cross my mind that it could be a fumble, bad move imo. Hopefully, the ref is on shrooms when he looks at the review.
Bad challenge. Even if the arm wasn't going forward (I think it was), I don't think there's indisputable evidence to overturn. Kubiak's decision-making on challenges has been atrocious during his entire coaching career.
That timeout would have been wasted by the offense anyway at one point. We never have all 3 to end the game.