Ahh, its definitely due to the hard ano.. Regular anodizing is usually fine, but in industry, hard ano most of the time we mask the threads before plating.Sorry man, meant to get back to you last night. The -12 fittings bind after about a turn AFTER running a tap through them after running a tap through them. Before, they'd catch almost immediately, maybe 1/3 of a turn. The adapter pictured is the same one with the issue. The fix has been to grind the threads down, seat the fittings, then weld them in place.
My request to Parts Badger was very specific. I told them it had to accept an AN12 fitting, which I verified in my design, in the request through their site, and again via e-mail. What you said about hard anodizing is something one of the shops brought up as well. They mentioned they had seen other issues similar to this where the part would normally fit but it wasn't designed with anodizing in mind. Considering anodizing is one of Parts Badger's options and they confirmed the fittings would fit, I didn't even consider this would be an issue.
I've certainly learned the hard way on this one. This is the first and last time I'll use an online CNC service for something like this.