You can download the files by going to the file section on the left panel, and then clicking on the file that you want to download. It should bring you to a page like this when you click on it.
I have the same problem, and the suggested solution does not work, because the file section on the left panel only stores files you uploaded or were already downloaded, not the ones that were generated by Julius and gave the error “Files only persist for 1 hour after their creation” when trying to download them. Is this a browser problem? I have this problem all the time, particularly with tables and I’m using chrome.