If your public-read bucket has index.html object present with content-type set to text/html; charset=utf-8. While accessing this object via web-browsers, it will render the content inline instead of downloading it as file.
I see you have one bucket that is public-read but it doesn’t contain index.html object in it.
Can you try with the content-type and if issue persists, please share the details. If you wish to share details privately - feel free to reach out to us at help@tigrisdata.com.