Also the rumble works and goes to both controllers. One peculiarity I noticed is that if I connect two controllers when the Deck is disconnect from a dock straight to the USB-C port I can control the game with both external controller and the built-in controls. Of course this could be a 'garbage-in garbage-out' fault state where the OS level is not telling the software accurate information about the state of the controllers and hence the logic does not simply know how to act when technically been given incorrect information. While there is a timeout I still find this kind of error behavior strange. It's bit weird that the Rogue Legacy 2 seems to halt the main thread while waiting some kind of reply from a rumble call. However the game did not freeze because of it. Before the fix I encountered the opposite problem with Celeste where I did not get any rumble with a PS5 controller. I'd take a guess that the problem could be related to the controller rumble fix done for Steam Deck earlier. Yeah, that controller number and order issue sounds very likely source of the problem as I had been using two controllers.

Instaling Rogue Legacy 2