Thats probably because as it's not quite all the way in there's some metal to metal contact between the link bracket and the shell of the mounting.Has helped no end with the annoying see-sawing of the engine but it does transmit more vibrations thru the body, i think due to not being fully seated.
Mine didn't go in quite all the way either so I just ground a bit off the edge of the mounting's shell where it stuck out of the housing to prevent it rubbing against the bracket and transmitting vibes.