And also, i can enable the setting, but pressing save makes a error pop up saying: “Could not save game settings” and the giant error pops up in the output.
Ask your friend to try. The 403 error implies a permissions issue for yourself. I’m not sure if it’s intentional due to the nature of the security settings, but if you can isolate whether it only happens to non-owners, then you have more information.
Try to recreate it on a new game under the same circumstances (you being a non-owner on a personal game) and see if the same happens. If so then it’s repeatable and you can create a bug report for it.