Spoke (wrote) too soon. The artifact is there, in the screen of the new
install.
After the intitial install and restart, it wasn't there, while the
system was running the intitial image from sda1. I then powered down and
booted into sdb1, and, of course, the artifact was still present (well,
w
Disregard the 1/25 12:37 AM message.
I reinstalled v18.04.3 and there's no problem with the system on that
drive (sda1). There's a clear sharp "Bionic Beaver" line drawing.
I had managed to complete the install last night on the drive I'd been
using, sdb2, and that still has the display problem
