On a similar note, I just finished an entire season with AC Milan without scoring from a corner once!
This despite having CBs with decent heights (Rami, Alex, etc).
In old FMs I would score loads from corners, I once had a CB called Geromel score 20 goals a season!
All of my CBs would regularly finish with 5-6 goals a season. Now they have none.
What am I doing wrong?
Have one player zonal mark the 6 yard box and it should reduce the goals drastically.
But having players who are poor at marking man mark on defensive set-pieces will get you punished as well.