Default platform for a group game should use group preference not user preference
I play on multiple platforms (and have them linked on my profile), yet when I create a group game for an Xbox group, it sets the game's platform to PS4 since that is my primary platform on my profile. This field is even hidden by default, so it's not obvious I need to change it. The platform should default to the group's platform when making a group game.
Brad Choate shared this idea