While a few high-end Nikon Z lenses are still made in Japan, the ‘Big N’ famously shifted Nikon camera production to Thailand back in 2020, with lens production now split between Japan, China, and more recently, Vietnam. As far as I was aware, only the Nikon Z DX MC 35mm f/1.7 is produced in Vietnam, but according to Nikon Rumors, it appears to have been joined by the Nikon Z 28-75mm f/2.8.
The rumor website was tipped off by the proprietor of another website called Photosynthesis, which is dedicated to cataloguing Nikon lenses. Although not confirmed by Nikon, an image of the Nikon Z 28-75mm f/2.8 clearly showing ‘Made in Vietnam’ on the underside of the barrel adds credence to the claim and you have to wonder if other optics could follow.