Shopping Cart Access when Wait List Capacity Equal to Zero

We have enabled the Fluid Configuration for the Enrollment Student Activity Guide, with all of the options checked. We are also aware of Doc ID 2811274.1 - Fluid Configuration Setup for Student Exceptions and Waitlist using the Student Activity Guide, where the Waitlist functionality works differently when the Enrollment Control is set to 0 for Wait List Capacity.

However, we have discovered that when the Enrollment Control is set to 0 for Wait List Capacity and the Open Enrollment Period has not begun, the class is not added to the Shopping Cart upon Submit. Instead, we only get the error, 'No Valid Appointment Found And Open Enrollment Period Has Not Begun. The open enrollment period has not begun and no valid enrollment appointment was found. The enrollment request was not processed.' The desired functionality is that the class would be added to the Shopping Cart, just as it is if the Enrollment Control is greater than 0 for Wait List