For Fedora 36+, we want to switch to using GNOME's upstream "dark / light" mechanism for backgrounds - where you can basically specify a dark background image, and a light background image, and if you use the 'light in the day, dark at night' theme GNOME will transition between the two for you - rather than using the older "ship an XML file defining an animated transition between two images" mechanism. The update that makes this change is in updates-testing already, but I'm filing a bug to propose it as an FE for Beta. It's not a huge deal, but since Beta's slipped again it seems worth getting it in. This setting is written to a user's profile when the user account is created and not updated after that, so right now everyone who installs F36 is getting the 'animated XML' setting, not the 'dark/light image' setting, and it won't be changed on subsequent updates even when the newer package is installed.
FEDORA-2022-d43d2cbe5c has been submitted as an update to Fedora 36. https://bodhi.fedoraproject.org/updates/FEDORA-2022-d43d2cbe5c
+3 in https://pagure.io/fedora-qa/blocker-review/issue/679 , marking accepted.
FEDORA-2022-d43d2cbe5c has been pushed to the Fedora 36 stable repository. If problem still persists, please make note of it in this bug report.