[CFD]

A couple of things I can think of that may be the problem. I haven't seen one to know but where as it seems most have trouble after tightening the screw it may be a tad to long, this will cause it to rub against the release mechanism not allowing it to return all the way, the other thing that comes to mind is if the base fits on the shifter shaft a little to loosely, when you tighten the screw it pulls the shifter forward possibly causing the release mechanism to bind against the back of the shifter. If anyone has one that is not mounted in the car, put the screw in the hole and take a picture so I can see how far it protrudes into the hole and that may give me an idea.