In a decision of June 15, 2012, (R 0021/11), the Enlarged Board of Appeal has referred a case back to the Board of Appeal due to deficiencies of the proceedings. In the objected proceedings, an expert opinion has not been considered and a request for admission of the expert opinion to the proceedings has been left unanswered. The deficiency in the proceeding is “relevant” in the meaning of Rule 104 b) EPC because the decision of the Board of Appeal possibly would have been different without this procedural deficiency. The objection of procedural deficiencies must be made explicit (“expressis verbis”).