I'm not talking about FTF/FTEs (I don't necessarily count them as gun-related, but perhaps Operator-related). I'm talking about broken parts. I've had the striker break on me in the HK second press of the trigger IIRC, my Kimber went full auto due to a bad sear (one of many problems with that one).
The ones I've witnessed, I don't know what the actual problems were, except that they were problems not field repairable.
I also recall seeing a Beretta and more than one M1911 launch parts of themselves downrange.
You live long enough, you'll find out that everything breaks. This is why you need to test any firearm you buy.
I wouldn't worry so much about cleaning, just read the manual and follow those instructions and you are good to go. My warning is about flawed materials that passed a quick inspection, but which may fail after many firings. Also, putting several hundred rounds downrange lets you develop a feel for how your pistol operates.