I mean, even if it is procedural - how the hell can CAS make a procedural mistake? Are the judges there 25-years-old just graduated or old, experienced judges? Even if, how can a court (I mean Swiss Federal) do not care whether the procedural mistake had an influence on the matter.
Last year there has been a case of Polish Curling Federation. The decision was "innocent" although the Federation did not fulfill its duty of checking sth, but as this sth did not influence on further decision, it was upheld.