diff --git a/README.md b/README.md
index 2212f4b..096947c 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,8 @@
 
 For custom logic, you can define functions in `eventHooks.lua`, hooks define event hook functions to be executed when their respective event happens. Use this when you need additional functional (such as posting to webhooks) when the shop starts, a purchase happens or fails, an error occurs, and other events.
 
+**IMPORTANT:** If you modify products' predicates in code (in event hooks), call `ScanInventory.clearNbtCache` as products cache which item nbt hashes match the predicates.
+
 # Layouts
 
 Radon has support for custom layouts in lua. While shops like Xenon are easier to configure, Radon offers a lot of flexibility, you get to write the code that renders the layout.
diff --git a/core/ShopState.lua b/core/ShopState.lua
index 313545c..b1c1c95 100644
--- a/core/ShopState.lua
+++ b/core/ShopState.lua
@@ -298,6 +298,7 @@
     self.currencies = {}
     self.kryptonListeners = {}
     self:setupKrypton()
+    ScanInventory.clearNbtCache()
     parallel.waitForAny(function()
         while true do
             local event, transactionEvent = os.pullEvent("transaction")
diff --git a/core/inventory/ScanInventory.lua b/core/inventory/ScanInventory.lua
index 9de2271..4750319 100644
--- a/core/inventory/ScanInventory.lua
+++ b/core/inventory/ScanInventory.lua
@@ -1,6 +1,7 @@
 local eventHook = require("util.eventHook")
 
 local itemCache = {}
+local nbtHashCache = {}
 
 local partialObjectMatches
 local function partialArrayMatches(partialArray, array)
@@ -55,12 +56,30 @@
     local matchingProducts = {}
     for i = 1, #products do
         local product = products[i]
+        if product.predicates and not product.predicatesString then
+            product.predicatesString = textutils.serialize(product.predicates)
+        end
         if item.name == product.modid then
-            if not product.predicates or predicateMatches(product.predicates, item, true) then
-                table.insert(matchingProducts, product)
+            if product.predicates and item.nbt and nbtHashCache[item.name .. "." .. item.nbt] then
+                for j = 1, #nbtHashCache[item.name .. "." .. item.nbt] do
+                    if nbtHashCache[item.name .. "." .. item.nbt][j] == product.predicatesString then
+                        table.insert(matchingProducts, product)
+                        break
+                    end
+                end
+            else
+                if not product.predicates or predicateMatches(product.predicates, item, true) then
+                    table.insert(matchingProducts, product)
+                end
             end
         end
     end
+    if item.nbt and not nbtHashCache[item.name .. "." .. item.nbt] then
+        nbtHashCache[item.name .. "." .. item.nbt] = {}
+        for i = 1, #matchingProducts do
+            table.insert(nbtHashCache[item.name .. "." .. item.nbt], matchingProducts[i].predicatesString)
+        end
+    end
     return matchingProducts
 end
 
@@ -139,6 +158,7 @@
     itemCache = items
     for i = 1, #products do
         local product = products[i]
+        product.predicatesString = nil
         product.quantity = product.newQty
         if product.bundle and #product.bundle > 0 then
             if not product.modid then
@@ -216,11 +236,19 @@
         items = getItemCache()
         sources, amount = findProductItemsFrom(product, quantity, items)
     end
+    for i = 1, #products do
+        products[i].predicatesString = nil
+    end
     return sources, amount
 end
 
+function clearNbtCache()
+    nbtHashCache = {}
+end
+
 return {
     updateProductInventory = updateProductInventory,
     getItemCache = getItemCache,
-    findProductItems = findProductItems
+    findProductItems = findProductItems,
+    clearNbtCache = clearNbtCache
 }
\ No newline at end of file
diff --git a/radon.lua b/radon.lua
index 9b1f50d..648d5b9 100644
--- a/radon.lua
+++ b/radon.lua
@@ -1,6 +1,7 @@
-local version = "1.3.22"
+local version = "1.3.23"
 local configHelpers = require "util.configHelpers"
 local schemas       = require "core.schemas"
+local ScanInventory = require("core.inventory.ScanInventory")
 local oldPullEvent = os.pullEvent
 os.pullEvent = os.pullEventRaw
 local oldPrint = print
@@ -323,6 +324,7 @@
                 if (not props.terminalState.configErrors or #props.terminalState.configErrors == 0) and (not props.terminalState.productsErrors or #props.terminalState.productsErrors == 0) then
                     props.configState.config.ready = true
                 end
+                ScanInventory.clearNbtCache()
                 local f = fs.open("products.lua", "w")
                 f.write("return " .. textutils.serialize(newConfig))
                 f.close()