Agent Studio:$context.$nodes.<nodeCode>.$feedbackReceived returns blank in (26C),

I’m building a Workflow Agent in AI Agent Studio (release 26C) with a Human Approval node that has feedback enabled. I want a downstream node to read the approver’s feedback, but the expression below return blank

Expression used {{$context.$nodes.[NODE_CODE].$feedbackReceived}}

I have feedback text from the approver, but the value is blank/empty

Is $feedbackReceived a supported variable for the Human Approval node? If not, what’s the correct path to the approver’s feedback text?
Does $output on this node include the feedback, and what’s its structure?
Does the answer differ by channel (Approval Process vs. email approver)?