Lee universal deluxe primer/decapper press

I’ve used this before, but it’s been about a year ago.  It worked fine then. Now I’ve placed the priming insert with correct large pin and spring in the press.  When I push the arm down it meets the shell, gives it a gentle push and then the shell goes up into the fingers (which are not broken) and doesn’t seat the primer.   What am I doing wrong? It need more resistance to push the shell down and seat the primer.