Since the rather large file that you uploaded has an extension of ".mp4", the Archive isn't deriving a smaller file from it. For example, if an uploaded file is named "Foo_bar.mkv", the Archive will ordinarily derive a (usually smaller) file named "Foo_bar.mp4".

However, if the uploaded file is named "Foo_bar.mp4", the name that the Archive would want to use would be the same.

The smaller files that the Archive would derive would be much more easily downloaded.

(The file that you see whose name ends with ".ia.mp4" wasn't produced by transcoding the uploaded file; it was produced by simply re-muxing the uploaded file so that there would be a streamable file.)

You could switch to using the Matroska container and the extension ".mkv", or you could continue to use the same container and use the extension ".mpeg4".

I believe that you can have smaller files derived from the files that you have already uploaded by clicking the "Edit" button and then selecting "I want to change the files in my item." This will allow you to change the extension from ".mp4" to ".mpeg4".

If the Archive doesn't automatically derive a smaller file after the renaming, you can hit the "Manage" button to take you to the "Item Manager" page and then hit the "Re-Derive" button.