Making a "Note to Approver" Field Required and Mandatory on the Oracle Award Negotiation Page

On the Award Negotiation page, we tried to make the "Note to Approver" field required using a page composer sandbox to restrict the buyer from submitting the award without entering a note to the approver. The sandbox made the field appear required with a "*", but if the buyer leaves it empty, it does not prevent the submission of the award for approval without adding the note.

Is there any solution for this?