When it happens, the trigger pull feels funny.
I've replaced the whole striker assembly; detail-stripped, cleaned, and degreased the slide guts; I've tried a couple different trigger bars (although I have one more combination of trigger bar and trigger mechanism housing to try).
About the only thing I haven't tried yet is swapping in a known-good firing pin safety & spring.
This is driving me bezonkoids, because it's such a fun little gun to shoot...