Hello :) 

I have my config set to false for stacking items with durability but they are still stacking. Does the global stack multiplier override this? Here is my config:

{
  "RevertStackSizesToVanillaOnUnload": true,
  "AllowStackingItemsWithDurability": false,
  "HidePrefixWithPluginNameInMessages": false,
  "GlobalStackMultiplier": 100.0,
  "CategoryStackMultipliers": {
    "Weapon": 1.0,
    "Construction": 1.0,
    "Items": 1.0,
    "Resources": 1.0,
    "Attire": 1.0,
    "Tool": 1.0,
    "Medical": 1.0,
    "Food": 1.0,
    "Ammunition": 1.0,
    "Traps": 1.0,
    "Misc": 1.0,
    "All": 1.0,
    "Common": 1.0,
    "Component": 1.0,
    "Search": 1.0,
    "Favourite": 1.0,
    "Electrical": 1.0,
    "Fun": 1.0
  },

Any help would be appreciated.

I am also having this issue

Fresh server, only this mod installed, global set to 2.0, set false to stackwithdurability, most durability items (except guns it seems) still stack x2, for example, the Stone Spear

I fixed this for myself by starting with a fresh config, turning off stacking durable items (just in case it starts working later) then creating a simple windows form application to search each line, split the string for the stack size at the end, and "if stack size != 1, double the amount on this line"

So essentially a simple text replacement program