I'm glad to hear that you fixed your problem. In my case I never replaced the actual trigger, I installed the Duty/Carry kit which includes the striker block and spring, and sear and trigger spring. I kept the stock trigger. My comments about Apex Tactical still apply. They have been great in helping me and went way beyond what they had to do to help.
After a very thorough cleaning and lubing with mil-comm products my Shield is operating well. I stopped using Froglube. I'm not saying that it was the cause of the problem, but I just couldn't accept the way it solidified on my Springfield TRP.
From my experience Froglube has worked very well on guns that are shot on a somewhat regular basis, but in the case of my TRP which set for a few months after cleaning with Froglube, it was for all intents practically locked up. I almost couldn't rack the slide. As a test, I took a hair dryer and heated it up and it loosened up to almost normal, but after cooling down it went back to where it was almost impossible to rack the slide.
After disassembling and thoroughly cleaning it, I lubed it with mil-comm and it's back to it's regular slick operation.
I've always been a big supporter of Froglube, but can no longer recommend it. I might use it as a protector for the finish on the outside, but for lubricating the internal parts I'll probably stick with mil-comm.