Two.
One from Incident with House Fire salvage that had been smoked, steamed, and wetted.
I had some misfires. I was not worried, considered them part of the practice. But then one squibbed and stuck a bullet. I pulled the rest to recover the bullets and brass.
One mismatched reload with too little powder and much air space, fired starting from a muzzle down "ready position." Erratic reports, then a stuck bullet with unignited powder behind it.