I have a different Manfrotto head than yours, same tripod, and my Hasse mounts solidly to the quick release plate and is quite solid even with the 150 on it. I had to get an insert for the bottom of the Hasselblad body to step it down for the normal tripod bolt. Maybe your adapter in the base of the camera isn't screwed in tightly enough.

Just checked. I have a 498RC2 ball head on mine. Nice solid head by the way.