Hi again,
I was able to test your experiment on a better connection. It does look like the browser starts fetching (partial) data from four videos from your server, but after that all requests stall. Because this doesn’t happen across all experiments on the farm, the issue must lie at least partly in how your server is configured to respond to the requests for video files that the farm sends it
Unfortunately, I cannot tell what server configuration controls that behavior, but I strongly encourage you to explore the zip file method, which will fetch all the video files from a single request to your server, and see if the problem persists
Jeremy