Odd, that brass looks like it has been reloaded.
The misfired cartridge sat in a stew of rain water, pine straw and willow oak leaves for two weeks. I'm sure the tannins/tannic acid did a lot for the cosmetics of the brass.
He was likely referring to the obvious junction of case web and case body that looks like the case has been resized.
The primer is also flattened, as if it's actually a fired primer.
I have a few boxes of that same ammunition, so I opened one and looked.
The Remington primers in the new cartridges look exactly like the one pictured, without of course the firing pin strike. They are seated as shown. The web junction is also evident.
The pictured cartridge is to my satisfaction a misfired factory round.