Strange "sandbox:" protocol links in AI response

I am developing plugin integration for my app. Everything is working great except when using AAA Slides (https://smart-slides.co/.well-known/ai-plugin.json) plugin, the links use strange sandbox: protocol even the response from the plugin server looks perfectly fine. Any idea why it does it and how to get correct links instead?

User request

Create a slide with the heading 'Test presentation' and the points 'One, Two, Three, Four'.

AI response

I have created a slide with the heading 'Test presentation' and the points 'One, Two, Three, Four'. You can download the slide presentation [here](sandbox:/slideshare/123456789).

Request and response from the plugin server:
request

{
  "slide_data": [
    {
      "heading": "Test presentation",
      "content": ["One", "Two", "Three", "Four"]
    }
  ]
}

response

{"download_link":"https://gptslidesbucket.s3.us-west-1.amazonaws.com/presentations/Presentation.pptx?AWSAccessKeyId=<ACCESS_KEY_REMOVED>"}