Flex Credits - employee can choose an amount more than allocated

Employee is allocated flex credits based on Salary.

Even though Allow Overspending Checkbox is unchecked in the configuration, the employee can choose an amount more than allocated and save the enrollments without any error.

Eg - Provided Credits- $10000 (Note -Based on employee Salary)

Used Credits - $53000

Unused Credits - $0

This is behaving inconsistently.

Sometimes The system throw an error as below:

Error

You're attempting to spend 40000 credits, which exceeds the maximum spending limit 10500 for this benefit offering. (BEN-991130) Details: Enter a different amount and try again.

Has anyone gone through this kind of behaviour?

Thanks,

Chaitra Subbu