Assuming the pistol chambers the rounds correctly and fully into battery, I think diagnosis is simple with one more critical piece of info:
Did the hammer fall all the way onto the firing pin when you experienced the 'delayed' fire?
If yes, then it's either hangfire due to bad ammo or misfire due to light strike. Sounds like you're describing hangfire, though. Change ammo or boost firing pin strike accordingly. The latter involves mainspring, mainspring plunger, mainspring housing, hammer strut, hammer pin, firing pin, firing pin spring, firing pin channel and firing pin hole in breechface.
If no, then it's a problem somewhere between the trigger and hammer. Complete disassembly and inspection might show you something that is obviously wrong, and it might not. Trigger bar, disconnector, sear, hammer, grip safety are involved. One or more could be out of adjustment, but hopefully someone at Factory 126 just left a chunk of ham sandwich in there.
