Yep, repeated it and made a screen video (and I was the person who also posted on the adobe forum…).
Here’s the video of the problem – note the files being erased from my hard drive at the end – they just disappear!
https://adobe.ly/2ZuDkLm
I’ve spent over 2 hours on the phone with Adobe support. They watch it happening with a screenshare, but haven’t yet found a solution. I’ve lost about 3 days of my time on this and am getting fed up.