My second Shield, a 4 inch Performance Center Shield Plus is giving me issues with not locking back on the last shot, I know that my right thumb touching the slide release is the issue. When I say " touching" I mean just that. Any contact with any oar of my hand seems to cause the failure. I never had this issue with my old shield or any other pistol. I know I can change my grip , but I have worked on the grip and trigger control and don't want to change things for one pistol…I won't. Are there any stiffer springs or fixes that can fix the issue? Thanks!