Yars ago, I had a factory .44 mag round go "Poof". Checked everything out, & found the bullet lodged in the forcing cone with enough clearance that I COULD have fired another round. Just good reinforcement to check CAREFULLY anytime everything doesnt seem just right.
Another time I was pulling down factory .300 Weatherby ammunition for case head expansion comparison tests, and found a curlique of brass that had somehow found it's way into the case before being loaded! It was about 1" long, and, in retrospect, I wish I had weighed everything out and recorded the details. Now, it's relegated to the file of odd things I probably don't need to know,,,,,,,,,,,,,,,,,,,,,,,Bug.