I'm not sure why, but I when my racing wheel and pedal setup was plugged in, the interface was accepting a slightly-turned steering wheel as the "down" input as if a user was holding down the down arrow. Naturally, this made the UI unusable.
This is totally an end-user issue, and super niche, though I wonder if the app has some device selection and handling logic that could be improved, should someone have controllers or other devices plugged in when running the isocon app.
0.8.2 windows version, windows 11.