Serenity BDD in Docker (Azure Pipeline) – PDF Download Triggers "Save As" Dialog Despite Configuration

I'm running Serenity BDD tests inside a Docker container as part of an Azure Pipeline. The tests are executed using Microsoft Edge (via Selenium Grid), and the video recordings are published as artifacts to help debug failures.

Currently I have the problem, that the "Save as" Screen is shown after a link gets clicked which downloads a PDF.

I've tried many things in my serenity.conf file like plugin.always_open_pdf_externally = false or download.prompt_for_download = false but nothing seems to work.

I guess the problem is the docker because the screenshots from Serenity BDD don't show any signs of this screen because it's outside the DOM.

Has anyone encountered this issue before with Serenity BDD or Selenium in Docker? Is there a reliable way to bypass the "Save As" dialog when downloading PDFs in Edge? Any tips on configuring Edge or the Docker container to handle downloads silently would be greatly appreciated.

My settings:

#serenity.conf 
webdriver {
    driver = remote
    autodownload = true
    remote {
        driver = edge
    }

    capabilities {
        browserName = "MicrosoftEdge"
        acceptInsecureCerts = true

        "ms:edgeOptions" {
            args = ["test-type", "ignore-certificate-errors", "inPrivate", "disable-infobars", "disable-gpu", "no-sandbox",
                "disable-default-apps", "disable-popup-blocking", "window-size=1600,1000"]

            prefs {
                download {
                    default_directory = "/home/seluser/Downloads/"
                    directory_upgrade = true
                }
                download.prompt_for_download = false
                plugins.always_open_pdf_externally = false
                profile.default_content_settings.popups = 0
                safebrowsing.enabled = true
            }
        }
    }

    timeouts {
        implicitlywait = 10000
        pageLoad = 600000
        implicit = 10000
    }
}

#docker-compose.yml
  edge_video:
    image: selenium/video:ffmpeg-4.3.1-20231020
    container_name: edge_video
    volumes:
      - c:/temp/selenium_videos:/videos
    depends_on:
      - edge
    environment:
      - DISPLAY_CONTAINER_NAME=edge
      - FILE_NAME=edge_video.mp4