I have this very weird glitch with Gnome, running on Xorg. I can move my mouse off the right hand edge of the screen, and the entire gnome UI starts to scroll over the the left, giving me a glitchy mess on the right hand side of the screen. The screenshot doesn’t really do it justice, because it just became transparent instead, but the transparent region where the terminal is should be off screen.
Hope I have explained that well, has anyone else hit that? I wonder if its due to multiple monitors, or non-aligned monitors?
The other links, which you described as irrelevant, were only a source of insight - in that it gives an idea about how each of these people seem to be getting a unique problem or issue, but then it is all boils down to some issues with the xorg configuration files, when you dig deeper into the forum article problems that they are facing, and what the people that answer them are suggesting them do.
If the arch wiki is not helping you solve it then you can try the other options or escalate it to a maintainer, because those arch wikis are maintained by people that needs to be notified when there is inconsistencies or bugs or issues that are not solveable regarding xorg and xrandr.
If you believe there is reason to suspect it is gnome/ mutter, and that you tested with i3;
it doesn’t tell us much, as i3 uses mostly a windows manager from what I know, whereas gnome/ mutter use GUI’s and thus requires its own configurations for the display. But if you still believe it is exclusively gnome’s/ mutters fault, you can raise it up to Gnome, then.