Social deduction plan &1 has already been approved

What causes this issue?

You tried to approve the document version of a social deduction plan for
which another approved version already exists. Both versions have the
same predecessor social deduction plan.

System Response

The system permits one approved social deduction plan version only.

How to fix this error?

Check which of the two document versions is to be approved. If
necessary, set the version of the social deduction plan that has already
been approved to 'Complete', and repeat the approval process.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.