Reference to the class characteristic will not be copied

What causes this issue?

You wanted to create a master inspection characteristic using a copy
model. However, the characteristic used as the model is linked to a
class characteristic and a class characteristic may not be linked to
more than one master inspection characteristic.

System Response

The link to the class characteristic is therefore not copied.

How to fix this error?

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.