Segment & has incorrect number for parent segment

What causes this issue?

Segment &v1& has segment &v2& as parent segment.
However, in the syntax entry for segment &v1&, there is an incorrect
item number for the parent segment.

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?

Error message extract from SAP system. Copyright SAP SE.