I also own a Patek with a 324SC and when the date gets into the 20s meaning 20 up to 31 I can ever so slightly
see the top of the next numeral 2 when I hold the watch at an angle. In my case it isnt enough that it bothers me
in the least bit. Perhaps yours is a little more further revealing of the next date.
Ive been monitoring it since ive bought it and it only seems to happen when it gets towards the date of 20 and higher.
By the way have you noticed any problems with the date changing at all? My watch is consistant and
switches very fast at about 11:58 pm. Its pretty amazing as most watches slowly turn the date many hours before midnight. From what Ive learned the 324 movement along with all pateks begins the date change around 10pm building up to that point.
I hope you get the date issue resolved...