What seems to have happened is that EASA wrote questions to NPA29 anticipating that it would be accepted and, when it was put on hold, mapped the relevant questions across to NPA25. From what we have seen your analysis seems correct, most of the questions can be validly mapped to NPA25, some of the new questions seem to be defective, but the biggest criticism is, as JPlumridge says, that the exams took a sudden change of direction which we could not anticipate. What happens now - in fact what has already started happening - is that we can redirect our students' study and provide relevant feedback so the pass rates come back up.
Data for BGS suggests a 50% fail for Op Procedures (A) and a 100% fail for Op Procedures (H) in the first week of the new exams. By the second week a number of candidates seem to have cancelled their sittings but of those few that sat 4 out of 5 passed (A) and 1 out of 1 passed (H). It looks like the only people that have been seriously disadvantaged are those that sat in that first week.
This is an issue that I will pursue, though. It is not, in my view, acceptable to introduce new material in volume in such a way that a large proportion of candidates fail through no apparent fault of their own . It is not sufficient just to say 'the questions were covered by the learning objectives', there is also a requirement to ensure that exams are balanced, consistent and fair.