There seems to be weird things happening with downloads.
I am using Google Chrome on Windows 10.
Google Chrome is up to date
Version 68.0.3440.106 (Official Build) (64-bit)
From the playtest page.. click the download all button
Page response is XMl, Access Denied - even though I am logged in as me.
From the content list, click the individual file.
Page refreshes after a second or two, the clicked item disappears. Wait a few second more, another page refresh happens, the clicked item is back with a problems downloading link.
No file as yet downloaded.
Click the problems downloading and you get the same page refreshes as before and no download starts.
So, I though I would try from my digital content.
Log in, shows all my digital content
Scroll down to the playtest bundle,
The rules update was added to my downloads, so I click it
Personalise, wait 60 seconds
Problems downloading link appears, but no file downloads.
Click the problems link.
Personalise message appears, sigh, we now have a no file download loop.
I hope there's enough detail here for you.