TMX here too. I had the issue in WTCR 2019 (tested 3 cars) but not with the '92 DTM 190E, so maybe its worse for FWD cars? Edited the .rcs file and the problem has gone. Changed back and the problem returned, although in my case the problem was not as consistent as you state. Lifting off the throttle usually results in what feels like a 'reset' of the FFB, it then behaves normally for a while until the next braking zone. My driver settings are at default, and I use the default profile in game with some button assignments. Seems to be working correctly with the 'flatspot' code disabled.