I noticed the brass shell casing has powder burns as well as as scratches on the shell. I guess those scratches were from the ejection process but the powder burn pattern is odd.
Almost lines up with the deformed backside of the round. Looks more like an actual accidental fire due to a strike on the rim before the round was lined up and fully in the chamber.
Is it possible it was not fully seated when you pulled the trigger? In other words, it didn't feed right?
What ever it was it is enough to frustrate anyone!