I think there's some amount of oddness that results from customizing a uniform (m -> e -> V) vs. assigning a uniform from a template (m -> e -> U). On a fresh embark bringing only four each (two pairs) of socks, gloves, high boots and gauntlets, I assigned a pair of each to two soldiers. For the first, I used a uniform template that included a single listing of each item. For the second, I initially assigned him "no uniform" and then custom built the uniform from the View/Customize tab, again choosing one listing of each item. Thus the uniform for each one appeared as such when viewed in View/Customize:
sock
high boot
glove
gauntlet
I did all of that before ever unpausing the game. I left the military screen and unpaused; the two soldiers ran to the wagon to gather their equipment. The one I'd assigned a complete uniform to took the items in the order listed, two of each as expected. The one I'd assigned equipment to in View/Customize, however, took one of each item initially, then a second of each one with the exception of gloves (he only ever equipped on glove, even when toggled on and off of training and/or duty).
That experiment by itself doesn't really help though. Why did only gloves bug for me, and only boots for BanjoSnake? And there are almost certainly a handful of relevant factors that I didn't even consider being an issue that may invalidate any results I could have shown here.