Indicator for returns item can no longer be changed

What causes this issue?

The returns item indicator has been changed manually or rederived
through input in another field (e.g. contract, purchase
requisition...).
However, a different value for this field is not allowed because
follow-on documents (possibly including cancelled follow-on documents)
exist.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.