I installed an APEX striker block in my M&P40c. It was installed correctly and now I am having issues with light primer taps and the firing pin not resetting completely sometimes. I am using quality factory ammo and standard mags. Has this happened to anyone else or any suggestions on a solution.

Are you by any chance referring to the striker safety plunger? If so, it sounds like the plunger is interfering with the striker. That's about the only thing that will cause the symptoms you describe.

Having checked the Apex website, the name you used on it is the one they use. It's not the S&W nomenclature.

I'd try removing the parts, striker included, and clean the striker tunnel, striker and plunger very well. You might have introduced some gunk while installing the Apex parts. You might also try reinstalling the factory parts and see what happens.

BTW, a good test firing technique is, WITH PISTOL VERIFIED UNLOADED, put a pencil down the bore hold the pistol vertical and see if the striker will launch the pencil.