Not all descriptions for value &1 could be copied

What causes this issue?

For the values of a characteristic, the description in a given language
must be unique.

System Response

A description of a value is not copied from the global to the
overwritten characteristic.
The description of a value in the global characteristic is identical to
another value or to a description of a value in the overwritten
characteristic.

How to fix this error?

Check the values and their descriptions in the overwritten
characteristic. If needed, change the description(s) manually in the
global or in the overwritten characteristic. Then try again to copy the
value.

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.