Cooling the cheesecake slowly in the oven is usually recommended to prevent rapid temperature drops, but it might not be the only factor involved in the cracking. Based on my experience preparing desserts for family gatherings, the issue could possibly stem from overbeating the eggs when incorporating them into the batter, which introduces excess air pockets. However, I am not entirely certain if this is the sole reason for your specific situation, as oven thermostats can vary significantly from what is displayed on the dial. You might want to look into whether the batter was mixed too vigorously, though other variables could also be responsible for the final result.