More info, really weird info.
All info 8/16/32 bit settings exhibit the same stuck row values.
No difference with any of the color settings or acceleration. 10 bits/ 8 bits same duplication. Fails.
Tried it on a friend's desktop system, Also current 64x Win 10. Works!
Then I tried dragging the Photoshop App window to my second monitor which is 8 bit cheapo. Works!
Dragged it back to the primary. Fails.
So, thinking what could be the same between the setups that failed? Well, they are all using high DPI displays, except the second display on my system (the one that works) isn't high DPI.
So then I looked at the Windows display magnification settings. My main system was set at 150% while the secondary display was at 100%, these were the default recommended setting. I changed the main to 100%. It now works. Changed it to 200%. Works. But 150% Fails and that's both the default for the 4K monitor and my preferred setting.
So then I changed the Surface Book which was at 225% where it fails to 200%. Works. Changed to 100% (tiny stuff). Works.
Conclusion: Most likely a Microsoft bug but given the whole row is effected and it makes 2 duplicates, to me it has a memory race condition smell.
I might try disabling all but one of the CPU cores and see if that also fixes it.