Error &1 when loading characteristic value assignment

What causes this issue?

An error occurred when loading the dialog.

System Response

The dialog display is not complete. You cannot assign values.

How to fix this error?

Exit the dialog and try to assign values to a different value
assignment type. If the error occurs again, notify your system
administrator.


Note for the system administrator:
The error may be caused by an incorrect entry in system table TCG11.

Error message extract from SAP system. Copyright SAP SE.