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Update: I cleaned up and tried an older BB in the shell. It is every so slightly out of alignment, but once tightened, not too noticeable. And more importantly, there is no resistance on the spindle. I'm not sure where to go from here. It could be the bottom bracket then I guess. Or just getting the thread looked at, as you say, may help. I really don't want to spend much more money on this!
Gotcha!
Either the shell needs to be faced or the threads need to be re-cut.
If when you install the BB there is an equal and opposite gap on the NDS, then the shell is off. This shouldn't present you with any problems unless you are using an external BB, as the cups are independent and wouldn't be parallel with each other.
However, from what you wrote originally I think the shell is threaded on the DS. This means the NDS and DS cups don't screw in parallel to each other and when you tighten them up the axle needs to bend to fit in cups. Obviously it can't so it binds the bearings.