Can replacing power steering control head, cause the power steering rack to leak on 2009 Mercedes-Benz GL550

My 2009 GL550 had its power steering control head replaced last week. Two days later the power steering went out. The dealership has said that the power steering rack now needs replaced. He stated that replacing the one lead to the other. Did the technician diagnosis the problem wrong?

Asked by for the 2009 Mercedes-Benz GL550