The sample model contains a hinge joint, and there is an important difference between how Mechanical and Discovery handle fixed and hinge joints. Discovery automatically trims the joint definition at the mesh level based on the overlap region between the two parts. This is done to prevent a rigid region from being created if a joint is created between a large surfaces and a small surface. Mechanical includes the full surfaces, which if not imprinted, can result in an physically unrealistic rigid region. This is reason why you are seeing the difference.
If you try to imprint the model in Discovery to allow the joint to be created only between the overlap between the two parts, then the peak stress location in Mechanical is in the same location as Discovery.
Thanks and Regards