I’ve had this issue for most of this year and have tried all sorts of fixes - certainly going to full flaps makes the bus unflyable. I use the TCA Captain’s Airbus hardware pack.
I usually disable the AP stable at 1000 feet with flaps 2 and almost immediately sink below the glideslope - I then get the Speed Speed warning and it just falls out of the sky.
I will try the slightly faster approach and flaps 3 as suggested here to see what difference it makes.
Fenix support was hopeless and closed my ticket to get rid of me.