Thanks for all of the additional replies. Sorry I've been so long with an update.
I took the bolt apart and inspected and cleaned. I didn't see anything that would cause a problem. Unfortunately I did this before reading the post about the firing pin safety block. Nothing stood out but I wasn't looking for that problem specifically. There were no gummy oils or greases. Everything was very clean with a very light oil.
I got a chance to go out and shoot 50 quick rounds this morning. This was S&B 124 grain fmj. The failure rate was down to only 1 in 50 on that particular box. The cartridge that failed to fire did fire on the 2nd try.
I don't have a stock scorpion trigger to compare it to but the hammer does feel on the weak side to me. There is practically no force left in the spring by the time the hammer reaches the vertical position. I may contact CZ or CZ Custom and see what they recommend.
Here are some images of the marks left on the primer. Scorpion on the left. P10C on the right.

