I have a M17 that's about 1.5 years old I have put 3-4k of rounds through.  I dry fire it a decent amount as well.  I had recently cleaned it and when I went to the range, there was a tiny additional "click" on pressing the trigger.  You pull the trigger, hit the wall, you can hear and feel a tiny "click" about halfway through the wall.  It shot normally that day and I haven't had a chance to look at it in detail.  It almost feels like there is a broken captured spring somewhere, where it still works but is broken and the "click" are the broken ends sliding over one another.  Anybody run into something similar?

Try a little grease on the firing pin safety spring?

Strip it down and examine every part. Check YouTube if you don’t know how to detail strip it.