BAdI system error: &1 is not &2% of &3

What causes this issue?

The BAdI implementation for MRM_RETENTIONS contains errors.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Contact your system administrator.

Procedure for System Administrators

The following formula is used to check whether the amount and the
percentage of the security retention match the item amount:
Retention amount = item amount * retention percentage / 100

Error message extract from SAP system. Copyright SAP SE.