When crafting kits get stacked, I can't find any way to unstack them. With (most) other items I place them in a crafting kit and it takes one from the pile, crafting kits stay stacked, like lockpicks. I assume this is a bug, because I can't see any logical reason why this would be (or why there isn't a more efficient way to unstack items).
Known bug because of how crafting kits interact (not like other items). I'm not sure if it's in any upcoming list for the next patches or not.