I have a similar issue with a Thrustmaster TMX setup connected to an Xbox1X.
I’ve set the max wheel rotation on the base itself to 270 degrees using the button sequence and I‘ve also cloned the TMX control set in the game and set that max rotation to also be 270 degrees (default is 360). Whilst in the pits, or completely stopped on track, the max rotation is indeed limited to 270 degrees, but once I start moving again, the wheel is allowed to rotate around a total of 450 degrees. (90 degrees more in each direction than what it is set up for)
I can’t wind enough lock on the wheel whilst holding it in my hands in the slow speed corners to turn the car effectively without having to let go with one hand and grab the wheel further round to pull down some more lock. This happens in both 2018 and 2019. I did update the FW on the wheel as per the Thrustmaster support site, but still no joy.