@Shibumi It could be scab. Golden Delicious is susceptible to scab and the other three major apple diseases. It also could to be some form of Summer rot. Perhaps it is bitter rot. You might take a look at this thread that discusses Summer rots.
If it occurs early in the season I think it is likely it is scab if it doesn’t show up until the Summer or later it’s more likely it’s a Summer rot. You would be better off planting an apple tree with resistance to multiple apple diseases like William’s Pride or Enterprise. There are other choices too. You might take a look at this apple disease resistance chart if you’re thinking of planting apples again.
Did you spray the apple trees?