Table & already has a field with name &

What causes this issue?

You attempted to append an indicator field to the base table, but a
field with this name already exists.

System Response

The process is terminated.

How to fix this error?

Please contact your system administrator.

Procedure for System Administrators

This is an internal error. The name of the indicator field was not
computed correctly. Please contact SAP.

Error message extract from SAP system. Copyright SAP SE.