Before revision:  A fully stabilized frame is required for equal order finite elements, both --proper for higher-order-- pressure Poisson stabilization in the bulk of the domain, as well as boundaryzone ]  ] velocity and pressure ghost penalty terms.
After revision:  A fully stabilized frame is required for equal order finite elements, both --proper for higher-order-- pressure Poisson stabilization in the bulk of the domain, as well as boundaryzone ] ], we use proper velocity and pressure ghost penalty terms.