diff --git a/bukkit/src/main/java/net/momirealms/craftengine/bukkit/plugin/network/handler/CommonItemPacketHandler.java b/bukkit/src/main/java/net/momirealms/craftengine/bukkit/plugin/network/handler/CommonItemPacketHandler.java
index 52359827c..a51598259 100644
--- a/bukkit/src/main/java/net/momirealms/craftengine/bukkit/plugin/network/handler/CommonItemPacketHandler.java
+++ b/bukkit/src/main/java/net/momirealms/craftengine/bukkit/plugin/network/handler/CommonItemPacketHandler.java
@@ -2,8 +2,10 @@ package net.momirealms.craftengine.bukkit.plugin.network.handler;
 
 import net.momirealms.craftengine.bukkit.item.BukkitItemManager;
 import net.momirealms.craftengine.bukkit.nms.FastNMS;
+import net.momirealms.craftengine.bukkit.plugin.reflection.minecraft.CoreReflections;
 import net.momirealms.craftengine.bukkit.plugin.user.BukkitServerPlayer;
 import net.momirealms.craftengine.bukkit.util.EntityDataUtils;
+import net.momirealms.craftengine.core.plugin.CraftEngine;
 import net.momirealms.craftengine.core.plugin.network.ByteBufPacketEvent;
 import net.momirealms.craftengine.core.plugin.network.EntityPacketHandler;
 import net.momirealms.craftengine.core.plugin.network.NetWorkUser;
@@ -27,6 +29,10 @@ public class CommonItemPacketHandler implements EntityPacketHandler {
             int entityDataId = FastNMS.INSTANCE.field$SynchedEntityData$DataValue$id(packedItem);
             if (entityDataId == EntityDataUtils.ITEM_DATA_ID) {
                 Object nmsItemStack = FastNMS.INSTANCE.field$SynchedEntityData$DataValue$value(packedItem);
+                if (!CoreReflections.clazz$ItemStack.isInstance(nmsItemStack)) {
+                    CraftEngine.instance().logger().warn("Invalid item data for entity " + id);
+                    continue;
+                }
                 ItemStack itemStack = FastNMS.INSTANCE.method$CraftItemStack$asCraftMirror(nmsItemStack);
                 Optional<ItemStack> optional = BukkitItemManager.instance().s2c(itemStack, (BukkitServerPlayer) user);
                 if (optional.isPresent()) {