Fwiw, the 562cf is an amazing knife. Great ergo's, buttery action, just sweet all the way around. Strictly my opinion, so take it for what it's worth. But if it were me, I'd start with giving the knife a nice warm bath. Basic dish soap, with running hot water. Hopefully break down and remove any grease or oil that trapping dirt, grime, or just metal bits from the shop. Then blow out and remove all moisture with an air compressor. Then test. If problem solved, great. I think some of the ZT's run just fine almost bone dry.
If it's better, but not 100%, my next step would be a wd40 bath. Flush with wd, work the action, and flush again. Finally, use air compressor again to remove all possible lubricant. Repeat if needed. With the air, I want to ensure removal of as much wd as possible. Even the smallest unseen trace of wd left behind will provide more than enough lubrication.
At least that is what I would do before returning. Ymmv. Gunk in a knife is not uncommon, and if you buy many, you'll probably run into this scenario again. Now if you try the above and still have issues, then at least you know you tried some basics, and it's time to let the dealer assist.
Enjoy the ride. [emoji16]