Went to the range today with my new 6.8 RRA 16" Middy upper on a spikes lower that I just built. This lower is my first build, but it wasn't too complicated and everything went together smoothly. I took it to the range to sight it in and after firing the first round, the bolt would eject that round, chamber a new one, but my trigger wouldn't work. This meaning that the only way to fire the next round would be to rotate the safety from the fire position back to safe and again back to fire. This seemed to reset the trigger and it would be good to go. My lower is a spikes and the parts kit is a Daniel Defense. When I came home, I compared the internals of the lower to another lower I have and it all looks the same. With the lower off the upper, you can cock the hammer and pull the trigger and it works everytime. I don't understand what it was doing. I did have an H2 buffer in the spikes and maybe that was causing the hammer to reset funny? I've got a standard buffer that I can try next time. Very strange. Thoughts?
Thanks for any help in advance.

Took it with me hunting this morning.  Oddly enough, switching the buffer from the H2 to a standard worked.  I ran 3 rounds through it to check and the trigger reset itself like it should.

Thanks for everyone's help.