Thanks for the input everybody. The troughs / roots are identical for every tooth, so I'm leaning toward the suggestions that it's a manufacturing defect. Maybe it was made after a lunch break with a little too much wine at the TA plant?

The chainring is used (it came on a different used bike) but it wasn't stock on that bike and other than this strange issue it looks to be like new. That little mark in the photo next to the C is dust, there are also a few grease/chain dirt smudges on it that wiped of easily.

On closer inspection, it looks like there's only one way to mount it since the bolt holes are recessed on one side. I'll try mounting it over the next week or two and let everyone know how it goes.