(i) Written decision deviates from oral decision
In T 425/97 the board decided that any substantive deviation of the decision notified in writing from that given orally at the oral proceedings amounted to a procedural violation. T 1365/09 held that a contradiction between the decision rendered at the oral proceedings and the written decision as sent to the parties contravened R. 111(1) EPC and amounted to a substantial procedural violation.
(ii) Decision deviates from previous communication
In T 2006/08 the board found that although the opposition division had expressed an opinion on the issue of sufficiency of disclosure in favour of the patentee in two communications, this opinion was clearly labelled as being preliminary and non-binding. The board also held that a preliminary, provisional opinion did not prevent a party from making its complete case. It was the responsibility of a party to ensure that the facts and evidence filed were not only unequivocally clear but also as complete as possible. If a party decided to retain or not to file further evidence to support its case, it would run the risk that an adverse decision might be issued based on the available (incomplete) evidence on file. The board rejected the request for reimbursement of the appeal fee.
In T 980/06, the contested decision had regarded a claim as patentable, whereas in the sole previous communication the examining division had taken a negative view. In such circumstances, a second communication would have been useful. However, its absence was not a "substantial" procedural violation.
(iii) Failure to deal with objection
In T 740/94 the board held that the failure of the opposition division to deal with an objection under Art. 100(b) EPC 1973 against an amended claim in its decision to maintain the patent in amended form clearly constituted a substantial procedural violation (see G 10/91, OJ 1993, 420, point 19 of the Reasons).
(iv) Third party observations not mentioned in decision
In T 283/02 the opposition division had duly forwarded the observations by third parties to the patentee, who had made no comment. The failure of the opposition division to mention these observations in its decision did not constitute a substantial procedural violation, even though a mention would have been desirable.
(v) Board decision containing similar facts not followed
In T 494/07 the board held that the strict legal obligation to follow the ratio decidendi of a decision of a board (Art. 111(2) EPC 1973) was limited to the same application and the same instance whose decision has been contested in the appeal, but did not extend to other applications (or even to other instances in the same application). This was so even if the subject-matter of the two applications was highly similar (see J 27/94, OJ 1995, 831).
(vi) Remarks on substantive matters in decision on admissibility
Remarks on substantive matters in a decision rejecting the opposition as inadmissible have no legal effect. Even if misleading, they do not represent a substantial procedural violation justifying the reimbursement of the appeal fee (T 925/91, OJ 1995, 469; see also T 1051/92).
(vii) Applying legal provision not yet in force
In T 991/02 an opposition division decision was set aside for lack of a legal basis. The opposition division's application of a new rule, not yet in force in this case, constituted a substantial procedural violation.