ubuntu mate 20.04.4 on adjusting display positions to match setup; one display background now blocky-flashy

Ubuntu-MATE QA-test install of 20.04.4 RC
- hp dc7700 (c2d-e6320, 5gb, nvidia quadro nvs 290)

NOTE: I bet this is a duplicate; but quickly sorry for QA-test records. Maybe filed on wrong package sorry (maybe why I'm not finding it).

Issue looks identical to https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/1942561 (that was impish)

Post-install checks I adjusted monitor to match my setup (one display above the other)

On lower display, the background is now blocky-somewhat-flashy (on changes to screen (including just moving the mouse IF mouse is on the other screen! but not my-lower screen) or blinking of a cursor in a data entry field)

The issue is only background, if TERMINAL or any window is maximized; the issue is gone (ie. blocky-flashy(changing graphics) is only occurring on background; windows are drawn correctly on issue.

See attached picture.

As I continued to use the system though (exploring it as I type this up on my primary box) the issue suddenly disappeared.. and it's now good.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xserver-xorg-video-nouveau 1:1.0.16-1
ProcVersionSignature: Ubuntu 5.13.0-30.33~20.04.1-generic 5.13.19
Uname: Linux 5.13.0-30-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.21
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: skip
CompositorRunning: None
CurrentDesktop: MATE
Date: Thu Feb 24 09:34:24 2022
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 NVIDIA Corporation G86 [Quadro NVS 290] [10de:042f] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: NVIDIA Corporation G86 [Quadro NVS 290] [10de:0492]
InstallationDate: Installed on 2022-02-23 (0 days ago)
InstallationMedia: Ubuntu-MATE 20.04.4 LTS "Focal Fossa" - Release amd64 (20220223)
MachineType: Hewlett-Packard HP Compaq dc7700 Small Form Factor
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.13.0-30-generic root=UUID=adf6196a-fec3-4c48-942c-a9b9b389de82 ro quiet splash vt.handoff=7
SourcePackage: xserver-xorg-video-nouveau
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/30/2006
dmi.bios.release: 1.5
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 786E1 v01.05
dmi.board.name: 0A54h
dmi.board.vendor: Hewlett-Packard
dmi.chassis.type: 4
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr786E1v01.05:bd08/30/2006:br1.5:svnHewlett-Packard:pnHPCompaqdc7700SmallFormFactor:pvr:rvnHewlett-Packard:rn0A54h:rvr:cvnHewlett-Packard:ct4:cvr:skuET090AV:
dmi.product.family: 103C_53307F
dmi.product.name: HP Compaq dc7700 Small Form Factor
dmi.product.sku: ET090AV
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.107-8ubuntu1~20.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 21.2.6-0ubuntu0.1~20.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.13-1ubuntu1~20.04.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1