The width of the container does not appear to be involved, I increased it, and the x-overflow is already set to visible, and I cannot see nor find any download button in the HTML.
Also if done properly the button should not disappear regardless of the width of the container, or else it would be lost on mobile or when the browser changes size. If properly done, the button would just move when the container is smaller.
But with overflow being set to visible, even if badly designed, it would still be visible.
Are you sure the download button is activated, and if so do you know where it is supposed to be?
Edit:
It looks like you have to be registered to access download. maybe you can create a temporary account for us to test.
If you do set your answer as Private, so the credentials are not public.