Workflow - not parsing multiple record values

I’m trying to grab all of the RecordIDs from an Airtable table (matching a criteria) and dump them into a long text field in a different table.

I’m using a Instant workflow triggered by an action button.

The Find Multiple Records just looks for records grabs a list of records from Airtable and then the Custom Code is supposed to bring all of these into a string. Here is the code:

and then in the Update record dialog I have this:

This produces absolutely nothing in the Notes field, despite running without errors.

Any ideas?