SC here and honestly it looks like a processing issue.
I'm 90% certain they incorporate the ingredients into water and create a slurry.
The slurry is likely cooked down or somehow they get most of the water to evaporate.
From there it's forced through a die with holes that gives it the pellet...
I was just searching the threads for this subject and I have gotten a similar bag twice within the last four months.
The first one had the same brown appearance and I'm guessing there is a tumbling/drying process that was overdone, because it had the same burned look to it and my chickens...