After not flying the plane for a long time I am flying the Airbus again. I noticed that I get into problems everytime during descent. At a certain time the plane switches to SPEED mode and then the green dot on the altitude tape drops down quickly meaning the plane can't keep the vertical path anymore. Of course I use the speed brake as soon as I see that happening but there is no way the speed brake can help here. Due to this I end up a few thousand feet (!) too high on approach. This has happened during all my (3) flights so far.
Anyone else having this? Is there something wrong with the AP logic somewhere? The next time I will simply start my descent early on (for instance as soon as the TOD comes into view on the display) but well, the plane obviously should be able to get to the correct altitude when you start the descent at the TOD...