Howie, most modern sealed tuners are supposed to be "permanently lubricated" meaning that the lubricant has nowhere to go, and dirt can't get in.
There's an easy way to track down the string possibility. Just pull one of the strings that's giving you trouble out of the nut slot and loosen and tighten the string. If it turns smoothly, you know the string has deformed and you need new ones. If the tuner is still tight, you know the problem lives there.
If it really is a tuner thing, Kamaka will want to know about it, and I'm pretty sure they'll make it right. If you end up needing to switch out the tuners, it's really no biggie. Most of the time, it's one screw and a nut, maybe one minute per tuner.
edit: When you look at the posts on your tuners (the metal pole that the string goes through) look at the place where it meets the headstock. You'll see a narrow nut that is used to hold the tuner in the headstock, usually supplemented by a screw in back. That nut can loosen up over time.