In T 450/97 (OJ 1999, 67), the board held that there was an obvious mistake within the meaning of R. 140 EPC if the text of a decision did not reflect the decision-making department's real intention. In T 715/14 the contested decision had referred to a communication dated 3 October 2013 although, undisputedly, the last-issued communication dated 19 April 2013 had been meant. Its correction had then introduced an additional reference to two other communications, which led the appellant to contend that it amounted to a subsequent change in the decision's content and the underlying reasons. The board, however, considered the correction permissible under R. 140 EPC because the communication dated 19 April 2013 was clearly and undisputedly meant and that communication referred to the other two.
In T 683/06, the board held that a correction under R. 140 EPC was not available for re-dating an application where its filing date had been deliberately chosen in a decision-making process (even if that process turned out to be mistaken).
In T 212/88 (OJ 1992, 28) the board held that the absence of a chairman's or minute-writer's signature at the end of an opposition division's decision was a rectifiable, obvious error within the meaning of R. 89 EPC 1973. In the case in question a second examiner had been referred to in the minutes as a member of the opposition division, although in fact he was not a member and did not take part in the oral proceedings (see also T 212/97).
In T 212/97 the board pointed out that R. 89 EPC 1973 permitted the opposition division to correct an obvious mistake in the copy of the decision notified to the parties. In the case at issue, a fourth person had been named as a member of the opposition division although no such person had been mentioned in the original document.