was also having a trigger recovery (dead trigger) problem so I thought I'd post some feedback on how I fixed mine...
After I installed the apex flat faced trigger, forward set sear, and ram I dry fired and everything was great as far as reset and trigger recovery. Took her out to the range and had some problems. I was able to shoot a few rounds and then the trigger would not recover. It was only a live fire problem. I tried a deep cleaning with no difference. Tried the stock sear spring with no difference. Was going to try a MA company sear spring but could not find one in stock. I had heard about some m&ps having bent trigger bars that excessively rubbed the frame and that sounded like mine. When I replaced the trigger bar I was able to see that it came in at a bit of a different angle, making no contact with the frame, and have had no trigger recovery issues since.
Edit: old trigger bar had an "H" stamp and the one I put in has an "S".