I own a 10x42 NL Pure along with a plethora of other binoculars. Been using it quite a bit for the past few months. Still on the fence on which I like better, the NL or the Zeiss Victory SF. Optics are very close and mostly a matter of preference. One obvious thing to me is the SF (although slightly larger) handles better, with better balance in the hand (less holding fatigue), and I prefer the SF focuser. Biggest negative for the SF is the eyecups which are much too fragile.
As far as the OP’s specific questions about identified issues with some NL samples, such as the focus stiction and fogging. First some background — a few years ago Swarovski made a corporate decision to move to less environmentally impacting materials in all of its product. This was noted in their company reports (there were no press releases to the Sports Optics Market [must not have been seen by the marketing folks as an advantage]). The immediate effects were the removal of SwaroClean external protective lens coatings (NL Pure doesn’t have it), a change to the external armor (NL Pure armor has some noted deterioration issues), and who knows about the once super-slick materials used throughout the mechanism. So, yes, there were impacts.
I live in a high-humidity area of the country and can say in my limited use, that while all optics fog during rapid changes changes in temperature and humidity (like moving from an air-conditioned vehicle to a humid summer day), I get the sense that the NLs externally fog a bit more easily than other premium offerings (how much so = TBD). As far as focus stiction - while it hasn’t happened to me I’ve read that this most commonly occurs in the NL after the device has been completely saturated. In addition, I’ve not heard of this since some specimens around the initial launch. So, SW might have made some changes to correct.
