3828512 - How does the audit rule 'Receipt Image Required - Entry Level' work?

I would like to understand how the Receipt Handling and Audit rule work when combined to prevent users from submitting reports without receipts.

I'm receiving the following exception message:

• Upload your receipts to expense line item using the Attach Receipt Images. In order for the red flag to be -reevaluated, you will need to click Submit again.

• Audit Rule Exception Code - NORCTRPT

Administrator would like to understand how the receipt handling and audit rule work together to prevent users from submitting reports without receipts. , KBA , CON-EXP-ADM-AUR , Audit Rules , CON-EXP-EXP , Expenses , Problem