It seems like last update cut low frequency sound from kerbs. I use a buttkicker and I am not able to “feel” the kerbs anymore.
I am on xbox series x.
The kerb sound is there but my buttkicker does not rumble anymore. So definitely something has changed in the game equalization, like they cut the low frequencies. On the other hand the title video (the car starting up) still has a lot of low frequencies, making my buttkicker rumble properly.
I’ve deleted my post since you’ve changed the explanation of your problem.
Because i don’t have that unit you’re using, i can’t tell if i also have this problem or not but,
at least my subwoofer still putting out some lows when hitting the curbs.