Hello, I have been flying all the A320 Professional family aircraft now and every time that I have flown the A321, problems occur on approach, once in Dublin and once just now in Oslo.
While approaching ENGM (INREX4L arrival, followed by ILS approach to runway 1L) the aircraft proceeded to nosedive at -8000 feet per minute from 9000 to 5000 feet. The aircraft descended from 9000 to 5000 in a fraction of the distance which it was supposed to. I immediately switched the AP off, pulled the plane out of the dive and flew it manually until switching the AP on just a few minutes later. The plane then didn't capture the ILS glideslope and localizer despite me following the correct procedures (given by the "Final" checklist in the PDF.) I turned the AP off again, followed the ILS down and landed the plane perfectly on the runway. After landing, nothing else seemed out of the ordinary.
This also occurred on approach to EIDW, however, that time I didn't switch the AP of to pull the plane out of the dive, I just let the AP take care of pulling up, and it eventually did. However, that time, the plane also didn't capture glideslope and localizer despite, again, following the correct procedure.
This problem only occurs with the A321, the A318, A319 and A320 seem to be fine for approaches, for now.
Any help would be much appreciated.