In &3 form bundle type &1 is already assigned to revenue type &2

What causes this issue?

You are trying to generate a form bundle type of form-based process
'TAX_RETURN' from the Customizing of revenue type &V2&. In time frame
&V3& of periodicity &V4&, the form bundle type &V1& is already assigned
to revenue type &V2&.

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?

Delete the validity of the relationship between revenue type &V2& and
the form bundle type to be generated.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.