I had a situation where the spindle's toe bushings were done and deflecting measureably. They just weren't up to fighting 330ft-lbs and a 4.36. Those bushings don't have a steel sleeve, and they are engineered to give before the traction and ruca bushings. Swapping to solids in all 3 locations made a huge difference in how bad it wandered under accel.

Also, corner weights off by a lot maybe? That's a bit of a longer shot.