I have been trouble shooting some intermittent ignition problems in a pair of P09 pistols, with Cajun Pro trigger packages installed by CGW.
With factory ammo, only on DA shots, very intermittent occurrences. After chasing a bunch of possibilities, I finally figured it out today, and can replicate the failure to ignite on demand. Here is the crazy part — the failure to ignite is completely based on how I press the DA trigger. Straight back and there are no issues. If I press with some slight deviation, I feel like my trigger finger tip is contacting the frame and preventing ignition. No marks on the primer.
Does it with two different P09 pistols, and follows even if I swap uppers. My stock P07 will not do this regardless of how I press the trigger.
Here is a video I made after I finally figured it out.