There is a minimum count for data to populated in unused signal report. You might not be hitting this minimum.
Pixel looks ok to me. My recommendation would be to create a trait/segment based on this and map it to a cookie destination. Then open the email in a browser that support the img request (confirm it fires in the network analyzer) and then go to the client.com site and check the response for the demdex call and confirm that you qualified for this trait/segment by seeing the segment mapping in the JSON response.