Grid Plus error: gridRecordField → “Record field input must not be null or empty” (query rule source, no value on column)

Product: Appian
Area: Interfaces → Plug‑ins → Grid Plus Layout (gridPlusLayoutField)
Appian version: [e.g., 25.3]
Database: MariaDB

Problem Summary

I’m displaying data in Grid Plus using gridPlusLayoutField + gridtextcolconfig, with the grid sourced from a query rule (Record DataSubset). When I configure a column using recordField: gridrecordfield(recordType!...fields.<key>), I’m getting:

Interface Definition: Expression evaluation error at function 'gridRecordField': 
Record field input must not be null or empty

I need to render null‑safe text (e.g., “-”, “Not Available”) for some fields, but my Grid Plus build does not support a value/valueFunction/valueExpression property on gridtextcolconfig.

Full Error

Interface Definition: Expression evaluation error at function 'gridRecordField' [line 36]:
Record field input must not be null or empty