Spaces CORS does not expose headers

I have been using Spaces in replace of S3 for a while. I am using custom metadata. The retrieval of my custom metadata is fine if I get the objects via either java AWS SDK or AWS CLI. However I cannot get it via javascript running on a domain. I have configured CORS for the bucket and notice that Digital Ocean does not provide a place to enter the ExposeHeaders configuration, which enable S3 CORS to return custom metadata for the objects. I even attempted to set the ExposeHeader myself for my bucket using AWS CLI, something like: aws --endpoint-url https://sgp1.digitaloceanspaces.com s3api put-bucket-cors --bucket mybucket --cors-configuration file://cors.json the cors.json file contains my settings for ExposeHeaders

getting back the CORS from DigitalOcean shows that my settings was saved, with the ExposeHeaders aws --endpoint-url https://sgp1.digitaloceanspaces.com s3api get-bucket-cors --bucket

However, there is still no metadata or any extra headers in my cross domain response . The only headers presented for my objects are: content-type and last-modified.

Is this a missing configuration on DO side? Thanks and regards, Nghia