No value assignment found for length characteristic of receipt

What causes this issue?

The heuristic could not find a value assignment for the length
characteristic for a receipt element. This value is needed to plan
standard lengths.

System Response

The heuristic tries to process the receipt element without the correct
length information. As a result, the assignments that are made may be
incorrect.

How to fix this error?

Add the missing value assignment for he length characteristic of the
receipt element.

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.