I have the same issue. My VC is up to date, but I am on an older version of WordPress with Woocommerce. Same thing here. Been baffled by this for about a month since updating VC to the newest version.
What happens with me is that when I create a product without a shipping weight then the permalink doesn’t get randomized. When I add a shipping weight, both the permalink and weight randomize! The only way I have managed to have the weight and the permalink save as I need them so far is to not have any numbers in the permalink. No numbers in the permalink seems to keep the weight as I need it to be and the permalink to not randomize.
