W-2 Box13 Unchecked for Roth 401K Deduction

When we ran the TAX504LD, the 401K and Roth 401K deductions codes were listed on the run control. We have since found out that Box 13 was not checked for employees who only contributed to Roth 401K. The employees have a balance in 2020 and the balance amount is in Box 12AA as expected. Box 13 is checked for employees who contributed to only 401K and those who contributed to both 401K and Roth 401K. Any idea why Box 13 would not have been checked for Roth 401K employees?