User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:108.0) Gecko/20100101 Firefox/108.0

Steps to reproduce:

Happens on Ubuntu 22.04.1 with Firefox 108.0.2 from the mozillateam ppa (https://launchpad.net/~mozillateam/+archive/ubuntu/ppa) in a wayland session.
This does not happen with obs-studio 27.2.3.

Go to https://webrtc.github.io/samples/src/content/getusermedia/getdisplaymedia/ click on "start", choose a screen from "Entire Screen" and click on "share".
You should be presented with a screen capture of your desktop.

System info
OS: Ubuntu 22.04.1 LTS
Kernel: 6.1.4
Gnome Shell: 42.5
pipewire: 0.3.48

Actual results:

Wayland and X11 cursors are visible at the same time.
That is, one cursor (Wayland) that moves and changes correctly, and another one that only moves when interacting with a window running via XWayland and stays in place otherwise.

Expected results:

Only one cursor is visible.

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Gtk' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Snapshot from screen share with two cursors: The correct one on the right, and a stationary one, that stopped moving after the actual cursor moved away from an X11 client, on the left.
I used emacs but any X11 client will do.

This still happens on Firefox 109.0 from the mozillateam ppa.

Hm, this looks likely a Mutter bug to me. I plan to look into some issues in that area in the coming days.