diff --git a/nms-patches/net/minecraft/server/AdvancementDataWorld.patch b/nms-patches/net/minecraft/server/AdvancementDataWorld.patch
index 7c005ced9..dd67145ad 100644
--- a/nms-patches/net/minecraft/server/AdvancementDataWorld.patch
+++ b/nms-patches/net/minecraft/server/AdvancementDataWorld.patch
@@ -1,7 +1,28 @@
 --- a/net/minecraft/server/AdvancementDataWorld.java
 +++ b/net/minecraft/server/AdvancementDataWorld.java
-@@ -1,3 +1,4 @@
-+// mc-dev import
- package net.minecraft.server;
+@@ -28,11 +28,15 @@
+ import net.minecraft.util.profiling.GameProfilerFiller;
+ import org.slf4j.Logger;
  
- import com.google.common.collect.ImmutableMap;
++// CraftBukkit start
++import java.util.HashMap;
++// CraftBukkit end
++
+ public class AdvancementDataWorld extends ResourceDataJson {
+ 
+     private static final Logger LOGGER = LogUtils.getLogger();
+     public static final Gson GSON = (new GsonBuilder()).create();
+-    public Map<MinecraftKey, AdvancementHolder> advancements = Map.of();
++    public Map<MinecraftKey, AdvancementHolder> advancements = new HashMap<>(); // CraftBukkit - SPIGOT-7734: mutable
+     private AdvancementTree tree = new AdvancementTree();
+     private final HolderLookup.a registries;
+ 
+@@ -56,7 +60,7 @@
+             }
+ 
+         });
+-        this.advancements = builder.buildOrThrow();
++        this.advancements = new HashMap<>(builder.buildOrThrow()); // CraftBukkit - SPIGOT-7734: mutable
+         AdvancementTree advancementtree = new AdvancementTree();
+ 
+         advancementtree.addAll(this.advancements.values());