Die cracks on the edges of the 4 corners of the building are common. While the die is forming the building, the die can crack as the metal is forced in the shape it must firm. This reminds me of a peanuts cartoon, I saw years ago:
Often we see at least 3 of the corners affected. But I found one with three die cracks not on the normal areas of the design:
These happen less on this design. But they are of interest to new ones. As you become a seasoned collector, they will see them as just die events. These can continue to get worse and sometimes a large number of die cracks can retire a die. But they are often continued to be used.