The third gen's are not as bad as 2nd's, but basically are the same system. The hydroboost favors brakes first, then steering. If you are on the brakes, the system uses up most of the pressure/flow on brake assist. What's left over is for steering. It gets worse with bigger/offset tires and wheels. It is the nature of the beast. Same system on Ford and Chevy.
If you are in a tight spot, especially backing a trailer slowly, it will sometimes be hard to impossible to steer, depending on how hard you are on the brakes, and angle of wheels.