Steam Controller registers as mouse/keyboard, breaking the UI

I use the second-generation Steam Controller (released last May), but skate. seems to register it as mouse and keyboard instead of a controller. Within minutes of playing the game (sometimes right away, sometimes it takes up to 5 min. or so), the UI shows a mouse pointer on screen and keyboard input in menus despite using the controller. In addition to UI inconveniences, this issue makes the radial menu unusable, as it selects the menu option wherever the absent mouse is pointing; I can't override this with my controller and therefore can't use certain game features (like selecting music or placing quick-drop objects).

Alt-tabbing temporarily resolves the issue, but it breaks again within minutes every time, making this workaround very short-lived, immersion breaking, and highly impractical.

I don't experience this issue with any other games, which is why it appears to be a skate. issue to me. I play the game through Steam, with the latest updates for the Steam Controller installed.

I tried to troubleshoot by using various settings for the Steam Controller, including factory resetting it. I tried avoiding the trackpads altogether. I tried setting the trackpads up in different ways (as joysticks, hotkeys, and as mice). I tried disconnecting and reconnecting the controller at various moments (before starting the game, in the main menu, while playing, in the in-game menus). None of this helped.

I hope to be able to play the game again soon using my preferred hardware.