All the drafts are being saved. If you go back to a draft you can do a few things, if for some reason you can't edit it. There is a Rollback button so you can rollback to whatever draft you want, provided you check the box for the draft version. And you should also see icons in the upper right of each article. One should be "get the article's HTML for editing offline." If you click that you should get that draft's HTML. That's how I sent you the HTML for that specific draft.
Then keep a local copy for yourself, just in case (that's always just a good practice) as you go along.
I didn't expect to find a draft in that list. Thanks.
But it doesn't work for me! When I choose the latest draft of Debugging Live Systems and try to compare it to the most recently published version, I see no changes at all, which isn't surprising because it says
Comparing revision 6 (Wednesday, February 5, 2020 10:47am) and revision 6 (Tuesday, February 4, 2020 2:49pm)