Transient field &1 requires the annotation '@ObjectModel.readOnly'.

What causes this issue?

In the consumption CDS view, a transient field can only be used in
read-only mode.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Add the annotation '@ObjectModel.readOnly:true' to the transient field
in the CDS view.

Procedure for System Administrators

Contact the corresponding developer of the CDS view to correct the
error.

Error message extract from SAP system. Copyright SAP SE.