Im currently decending into LPPT and I was told to decend to 7000ft. I set 7000 and saw that my alt just kept decending below my selected alt. I thought that it was going to go a little bit below as I was on a rapid decent but by the looks it just kept decending to about 3500 until I realised I should take manual control.
Device: Ipad 2018
Aircarft: B737 BBJ