That’s part of the same issue - the default UE 5.1 UCommonUIActionRouterBase::ApplyUIInputConfig implementation, while it works for Fortnite and Lyra, doesn’t work well for other types of games. It must be overridden.
Basically any time any of the Common UI widgets change the UI state, this function gets run, which is then going to totally mess up your UI in a non-shooter type game. (Unless/until you override it and have it do the correct thing for your game).
Once 5.2 releases, this function (and the variable it needs to set) should be protected virtual, and so then you’ll be able to customize this stuff without having to build a custom engine.