I have the same exact problem with my 2019 Lexus 450H. I have taken my car in for a detailed inspection of the drivers seat. I was told that this bump is an "inherent characteristic" of the seat. Well it is an inherent flaw! I am of small frame, and have had two low back surgeries in the past three years. The last surgery, relieved my low back pain and leg pain. However when I drive my car, I cannot be in it long as it causes these symptoms. The pain eases out after a few hours when I'm done driving but returns if I drive the car again. I have had my coccyx bone and and then my sacrum bone adjusted in the past few months by my physical therapist. I have been released from official physical therapy treatments, so this is an out of pocket expense. I was told that this problem is from sitting at an angle. I do this to avoid the bump. Also, I paid $400 for new lambs wool seat covers, but they did nothing to help. I drive with two folded washrags on each side of the lump to help minimize its height. Ridiculous to have to do this for a car that is considered a "luxury" vehicle. I have just taken the car in for a recall of the fuel pump. Supposedly they will check into replacing the seats. But then again, no one called me to give me an update, even though they said they would. I will check again next week. I was told that there is no other seat design that can be put in its place. However, I did drive a 2021 (same model). The back of the seats are softer, and the base of the seat still has the lump but it is not as noticeable. My husband does not feel the bump, but others do. I cannot drive a vehicle that causes me pain. We had a 2010 Lexus 350RX which I drove for 10 years. Loved that car, but dread driving the one I have now. If Lexus does not try to help solve this issue, we have no choice but to sell the vehicle.
