This is an update to my previous thread with a perhaps more narrowed down problem description.
I will link a video https://imgur.com/a/6d6VXsV
Note that I was able to keep that black rectangle staying there permanently unless I moved or moved the camera as shown. Taking advantage of that, with the black rectangle fixed there, I took several screenshots. Nothing came up in the screenshots and no anomalous rectangles could be seen, so I think this has to do with my display.
No load on my CPU or GPU. Temperatures not unhealthy. What’s going on here and how do I fix this? I have a 240 Hz monitor. I’ve tried changing to 60 Hz and it hasn’t fixed it. This is a laptop.
Oh - and I’d like to point out that I’ve only seen this issue appear in WoW. Not in any other games I’ve played (Overwatch for example).
Quite the interesting effect you captured there, Modaro.
If none of these black rectangles show up in WoW screenshots it does mean they are not being produced by the game itself but are somehow “superimposed” on top of what the game happens to be displaying at the time. A mechanical problem with the display screen would certainly be possible, but those shapes are a bit too regular and “neat” (for lack of a better word) for that to be my first guess - I’d honestly expect this to be some form of display overlay that usually is transparent but ends up being visible at times.
I’d suggest looking into background applications running on the laptop - programs like Overwolf, Nahimic, MSI Afterburner, Discord and various display driver tools all have the ability to project information windows on top of a game, and if that goes wrong it could look a lot like that. If you can’t find anything running that’d explain this you’d also be welcome to create an MSINFO log, upload it to a site like pastebin and post the link here - we’d be glad to have a look at the recorded data, it might shed some more light on things. 
I’ve tried closing a ton of stuff that was open using Task Manager. Discord, Nahimic, etc. A bunch of stuff – everything that I could think of possibly suspect would cause problems. No dice. Oh - and I’d like to point out that I’ve only seen this issue appear in WoW. Not in any other games I’ve played (Overwatch for example).
I’ve provided some links to help people look through (note, these were generated with a bunch of stuff closed in Task Manager – not sure if that matters. I can do this again with the typical stuff opened either way but the problem still persists when I generated these):
MSInfo:
https://pastebin.com/Akf2MEts
DxDiag (from System tab)
https://pastebin.com/jyiG0Vbq
DxDiag (from Display 1 tab)
https://pastebin.com/npXPQerD
DxDiag (from Display 2 tab)
https://pastebin.com/79C5BRWS
Here’s hoping you or someone finds out what the issue is! 
Any updates on this/looked into the links sent?
Sorry it took a bit to reply on this Modaro - things are somewhat hectic at the moment, what with everything going on globally and our offices being quarantined as a result.
From the collected data it appears that (at least at the time the log was created) the Nahimic services and their related overlay functions were still running. Given Nahimics overlays happen to have the pretty much exact shape of the ominous black rectangles seen in your video that puts the program fairly high on the list of “suspects” - would you mind fully uninstalling the software for a try, just to see if that makes any difference at all?
Beyond that: it may be worth a shot to connect the laptop to an external display screen, just to see if the effect carries over. If it does that’d further support the theory that the laptops own screen is not actually at fault here- some very rare mechanical faults would still be possible of course, but it’d somewhat strongly hint at a conflict on software level since said faults would typically show up in all kinds of applications.
Hey, thanks for getting back to me. No problem at all for the wait. I’ve tried disabling NahimicService in system configuration, but I’ve not been able to uninstall it. I can’t find it when under “Add/remove programs”.
I’ve gone into System32 and deleted all files with the words Nahimic in them, except for NahimicAPO3ConfiguratorDaemonModule.dll and NAHIMICV3apo.dll which couldn’t be uninstalled as I was told they’re open in audiodg.exe. Not sure what this means.
Anyway, so Windows is saying it’s disabled in Task Manager and System Configuration, but the problem is persisting and I can’t find anything about uninstalling Nahimic. Pressing the windows key and searching Nahimic doesn’t show anything either.
Here are updated logs:
MSInfo (had to use a different paste website since it exceeded limit)
https://controlc.com/bb5cc262
DxDiag:
https://pastebin.com/Ey1j1qqi
“Audiodg.exe” is a part the Windows audio environment, basically a component of the operating system that deals with audio/voice output. Nahimic itself is a “third-party” (meaning: not part of Windows) audio visualization overlay, so its service would indeed generally run as a default (at least in the background) while the computer has an audio device active - and it’d make sense that you’d not be able to remove its files while they’re still active in memory. It is somewhat unusual for a program to be this hard to remove, tho… it may be a good idea to reach out to the software manufacturer on that.
Booting Windows in “safe mode” and trying to remove the software like that may be worth a shot, too.