"you can clearly see some of the hub grooves on one side while the other side is snug"
That definitely warrants a very close look at the freehub splines, freehub stop, and each individual cassette cog and spacer...hopefully it's just some kind of burr or machining error that can be filed away - and not a bent cog or something.
=8-)
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5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life