I used the 20.04 Xub test DE on an AMG Picasso desktop machine for over a week without this problem - although it had failed to detect the usual display setting

I used the 20.04 Xub test DE on an AMG Picasso desktop machine for over a week without this problem - although it had failed to detect the usual display setting I use, which I'd had to fix with xrandr. (I'd had to xrandr Mint 19 too, but it stayed fixed.) However, on the day I tried switching to the XFCE DE, then switched back to the Xub DE, I was greeted by the block staircase display. Later I found that by replacing the 'home' folder with the installed original, it was gone. But only one (the wrong) display setting worked. Glad to see this is getting attention. For that first week, 20.04 was a rock.